[media] v4l2-ioctl: fix sparse warnings

drivers/media/v4l2-core/v4l2-ioctl.c:1156:53: warning: incorrect type in initializer (different address spaces)
drivers/media/v4l2-core/v4l2-ioctl.c:1158:42: warning: incorrect type in initializer (different address spaces)
drivers/media/v4l2-core/v4l2-ioctl.c:1161:34: warning: incorrect type in assignment (different address spaces)
drivers/media/v4l2-core/v4l2-ioctl.c:1163:35: warning: incorrect type in assignment (different address spaces)

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>