[media] v4l2-common: fix warning when used on userpace

As reported by Linus, make headers_check is reporting:
   usr/include/linux/v4l2-common.h:72: found __[us]{8,16,32,64} type without #include <linux/types.h>

   which seems to have come in through commits 777f4f85 and
   254a4777.

That happens because struct v4l2_edid should be visible by both
subdev and V4L2 APIs. So, it was moved to v4l2-common.h.

As Linus pointed, the proper fix is to just add an include for
linux/types.h at v4l2-common.h.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>