staging:rtl8821ae:Fix sparse warning of static function declaration

This patch makes the function _rtl8821ae_map_hwqueue_to_fwqueue
static as it is used only in the file trx.c.
Signed-off-by: NHimangi Saraogi <himangi774@gmail.com>
Signed-off-by: NPeter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>

drivers/staging/rtl8821ae/rtl8821ae/trx.c

@@ -38,7 +38,7 @@
 #include "led.h"
 #include "dm.h"
 
-u8 _rtl8821ae_map_hwqueue_to_fwqueue(struct sk_buff *skb, u8 hw_queue)
+static u8 _rtl8821ae_map_hwqueue_to_fwqueue(struct sk_buff *skb, u8 hw_queue)
 {
 	u16 fc = rtl_get_fc(skb);