ice: Fix the calculation of ICE_MAX_MTU

Currently ICE_MAX_MTU subtracts only ETH_HLEN from max frame size and
adds ETH_FCS_LEN and VLAN_HLEN, which is not what was intended.
The ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN expression should be surrounded
with parentheses.

Wrap mentioned expression and take into account VLAN double tagging.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ice/ice.h

@@ -83,7 +83,7 @@ extern const char ice_drv_ver[];
 #define ICE_DFLT_NETIF_M (NETIF_MSG_DRV | NETIF_MSG_PROBE | NETIF_MSG_LINK)
 
 #define ICE_MAX_MTU	(ICE_AQ_SET_MAC_FRAME_SIZE_MAX - \
-			 ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN)
+			(ETH_HLEN + ETH_FCS_LEN + (VLAN_HLEN * 2)))
 
 #define ICE_UP_TABLE_TRANSLATE(val, i) \
 		(((val) << ICE_AQ_VSI_UP_TABLE_UP##i##_S) & \