drivers/video/mmp/core.c: using plain integer as NULL pointer

drivers/video/mmp/core.c: using plain integer as NULL pointer

Sparse complains here:

	drivers/video/mmp/core.c:33:16:
		warning: Using plain integer as NULL pointer

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Andrei Epure <epure.andrei@gmail.com>
Cc: Lisa Du <cldu@marvell.com>
Cc: Zhou Zhu <zzhu3@marvell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>