v4l2-controls: add a missing include

As warned by "make headers_check", the definition for the linux-specific
integer types is missing:

	./usr/include/linux/v4l2-controls.h:1105: found __[us]{8,16,32,64} type without #include <linux/types.h>

Fixes: c27bb30e ("media: v4l: Add definitions for MPEG-2 slice format and metadata")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>