docs: networking: convert 6lowpan.txt to ReST

- add SPDX header;
- use document title markup;
- mark code blocks and literals as such;
- adjust identation, whitespaces and blank lines;
- add to networking/index.rst.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

Documentation/networking/6lowpan.txt → Documentation/networking/6lowpan.rst

+.. SPDX-License-Identifier: GPL-2.0
 
-Netdev private dataroom for 6lowpan interfaces:
+==============================================
+Netdev private dataroom for 6lowpan interfaces
+==============================================
 
 All 6lowpan able net devices, means all interfaces with ARPHRD_6LOWPAN,
 must have "struct lowpan_priv" placed at beginning of netdev_priv.
 
-The priv_size of each interface should be calculate by:
+The priv_size of each interface should be calculate by::
 
  dev->priv_size = LOWPAN_PRIV_SIZE(LL_6LOWPAN_PRIV_DATA);
 
 Where LL_PRIV_6LOWPAN_DATA is sizeof linklayer 6lowpan private data struct.
-To access the LL_PRIV_6LOWPAN_DATA structure you can cast:
+To access the LL_PRIV_6LOWPAN_DATA structure you can cast::
 
  lowpan_priv(dev)-priv;
 
 to your LL_6LOWPAN_PRIV_DATA structure.
 
-Before registering the lowpan netdev interface you must run:
+Before registering the lowpan netdev interface you must run::
 
  lowpan_netdev_setup(dev, LOWPAN_LLTYPE_FOOBAR);
 
 wheres LOWPAN_LLTYPE_FOOBAR is a define for your 6LoWPAN linklayer type of
 enum lowpan_lltypes.
 
-Example to evaluate the private usually you can do:
+Example to evaluate the private usually you can do::
 
-static inline struct lowpan_priv_foobar *
-lowpan_foobar_priv(struct net_device *dev)
-{
+ static inline struct lowpan_priv_foobar *
+ lowpan_foobar_priv(struct net_device *dev)
+ {
 	return (struct lowpan_priv_foobar *)lowpan_priv(dev)->priv;
-}
+ }
 
-switch (dev->type) {
-case ARPHRD_6LOWPAN:
+ switch (dev->type) {
+ case ARPHRD_6LOWPAN:
 	lowpan_priv = lowpan_priv(dev);
 	/* do great stuff which is ARPHRD_6LOWPAN related */
 	switch (lowpan_priv->lltype) {
@@ -42,8 +45,8 @@ case ARPHRD_6LOWPAN:
 	...
 	}
 	break;
-...
-}
+ ...
+ }
 
 In case of generic 6lowpan branch ("net/6lowpan") you can remove the check
 on ARPHRD_6LOWPAN, because you can be sure that these function are called

Documentation/networking/index.rst

@@ -33,6 +33,7 @@ Contents:
    tls
    tls-offload
    nfc
+   6lowpan
 
 .. only::  subproject and html