V4L/DVB (6814): Makefile: always enter video/

Since not all code under drivers/media/video/ depends on
CONFIG_VIDEO_DEV we cannot only enter it depending
on CONFIG_VIDEO_DEV.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>