staging: brcm80211: fullmac: fixed double #include

Fix double include as detected by checkincludes script.
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/brcm80211/brcmfmac/wl_cfg80211.c

@@ -21,7 +21,6 @@
 #include <linux/sched.h>
 #include <linux/kthread.h>
 #include <linux/netdevice.h>
-#include <linux/sched.h>
 #include <linux/bitops.h>
 #include <linux/etherdevice.h>
 #include <linux/ieee80211.h>