staging: wfx: place hif_tx_mib functions into a .c file

Until now, all functions from hif_tx_mib.h are declared "static inline".
However, they are not time critical. So, it does not make so much sense.

We prefer to place them in a .c file as for other hif functions.
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20200406111756.154086-9-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/Makefile

@@ -7,6 +7,7 @@ wfx-y := \
 	bh.o \
 	hwio.o \
 	fwio.o \
+	hif_tx_mib.o \
 	hif_tx.o \
 	hif_rx.o \
 	queue.o \

drivers/staging/wfx/data_tx.c

@@ -6,6 +6,7 @@
  * Copyright (c) 2010, ST-Ericsson
  */
 #include <net/mac80211.h>
+#include <linux/etherdevice.h>
 
 #include "data_tx.h"
 #include "wfx.h"

drivers/staging/wfx/key.c

@@ -5,6 +5,7 @@
  * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
  * Copyright (c) 2010, ST-Ericsson
  */
+#include <linux/etherdevice.h>
 #include <net/mac80211.h>
 
 #include "key.h"

drivers/staging/wfx/sta.c

@@ -5,6 +5,7 @@
  * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
  * Copyright (c) 2010, ST-Ericsson
  */
+#include <linux/etherdevice.h>
 #include <net/mac80211.h>
 
 #include "sta.h"