docs: net: ieee802154.rst: fix C expressions

There are some warnings produced with Sphinx 3.x:

	Documentation/networking/ieee802154.rst:29: WARNING: Error in declarator or parameters
	Invalid C declaration: Expecting "(" in parameters. [error at 7]
	  int sd = socket(PF_IEEE802154, SOCK_DGRAM, 0);
	  -------^
	Documentation/networking/ieee802154.rst:134: WARNING: Invalid C declaration: Expected end of definition. [error at 81]
	  void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi):
	  ---------------------------------------------------------------------------------^
	Documentation/networking/ieee802154.rst:139: WARNING: Invalid C declaration: Expected end of definition. [error at 95]
	  void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb, bool ifs_handling):
	  -----------------------------------------------------------------------------------------------^
	Documentation/networking/ieee802154.rst:158: WARNING: Invalid C declaration: Expected end of definition. [error at 35]
	  int start(struct ieee802154_hw *hw):
	  -----------------------------------^
	Documentation/networking/ieee802154.rst:162: WARNING: Invalid C declaration: Expected end of definition. [error at 35]
	  void stop(struct ieee802154_hw *hw):
	  -----------------------------------^
	Documentation/networking/ieee802154.rst:166: WARNING: Invalid C declaration: Expected end of definition. [error at 61]
	  int xmit_async(struct ieee802154_hw *hw, struct sk_buff *skb):
	  -------------------------------------------------------------^
	Documentation/networking/ieee802154.rst:171: WARNING: Invalid C declaration: Expected end of definition. [error at 43]
	  int ed(struct ieee802154_hw *hw, u8 *level):
	  -------------------------------------------^
	Documentation/networking/ieee802154.rst:176: WARNING: Invalid C declaration: Expected end of definition. [error at 62]
	  int set_channel(struct ieee802154_hw *hw, u8 page, u8 channel):
	  --------------------------------------------------------------^

Caused by some bad c:function: prototypes. Fix them.
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/networking/ieee802154.rst

@@ -26,7 +26,9 @@ The stack is composed of three main parts:
 Socket API
 ==========
 
-.. c:function:: int sd = socket(PF_IEEE802154, SOCK_DGRAM, 0);
+::
+
+    int sd = socket(PF_IEEE802154, SOCK_DGRAM, 0);
 
 The address family, socket addresses etc. are defined in the
 include/net/af_ieee802154.h header or in the special header
@@ -131,12 +133,12 @@ Register PHY in the system.
 
 Freeing registered PHY.
 
-.. c:function:: void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi):
+.. c:function:: void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi)
 
 Telling 802.15.4 module there is a new received frame in the skb with
 the RF Link Quality Indicator (LQI) from the hardware device.
 
-.. c:function:: void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb, bool ifs_handling):
+.. c:function:: void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb, bool ifs_handling)
 
 Telling 802.15.4 module the frame in the skb is or going to be
 transmitted through the hardware device
@@ -155,25 +157,25 @@ operations structure at least::
         ...
    };
 
-.. c:function:: int start(struct ieee802154_hw *hw):
+.. c:function:: int start(struct ieee802154_hw *hw)
 
 Handler that 802.15.4 module calls for the hardware device initialization.
 
-.. c:function:: void stop(struct ieee802154_hw *hw):
+.. c:function:: void stop(struct ieee802154_hw *hw)
 
 Handler that 802.15.4 module calls for the hardware device cleanup.
 
-.. c:function:: int xmit_async(struct ieee802154_hw *hw, struct sk_buff *skb):
+.. c:function:: int xmit_async(struct ieee802154_hw *hw, struct sk_buff *skb)
 
 Handler that 802.15.4 module calls for each frame in the skb going to be
 transmitted through the hardware device.
 
-.. c:function:: int ed(struct ieee802154_hw *hw, u8 *level):
+.. c:function:: int ed(struct ieee802154_hw *hw, u8 *level)
 
 Handler that 802.15.4 module calls for Energy Detection from the hardware
 device.
 
-.. c:function:: int set_channel(struct ieee802154_hw *hw, u8 page, u8 channel):
+.. c:function:: int set_channel(struct ieee802154_hw *hw, u8 page, u8 channel)
 
 Set radio for listening on specific channel of the hardware device.