Fix build failure at cx25821-video driver

Kernel build fail for cx25821-video has depends on smp_lock.h header
file, but the dependency is removed in recent commit 451a3c24b013.

Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

authored by Youquan Song and committed by Linus Torvalds 2811036a ed1d77b1

+1
+1
drivers/staging/cx25821/cx25821.h
··· 31 31 #include <linux/delay.h> 32 32 #include <linux/sched.h> 33 33 #include <linux/kdev_t.h> 34 + #include <linux/smp_lock.h> 34 35 35 36 #include <media/v4l2-common.h> 36 37 #include <media/v4l2-device.h>