brcmfmac: include linux/atomic.h

brcmfmac uses atomic_or() and other atomic_* functions, but does not
include linux/atomic.h. This file gets included by some other header
file so this normally does not cause problems.

Signed-off-by: Hauke Mehrtens <[e-mail]>
Acked-by: Arend van Spriel <[e-mail]>
Signed-off-by: Kalle Valo <[e-mail]>

drivers/net/wireless/brcm80211/brcmfmac/sdio.c

···
  */
 
 #include <linux/types.h>
+#include <linux/atomic.h>
 #include <linux/kernel.h>
 #include <linux/kthread.h>
 #include <linux/printk.h>