V4L/DVB: saa7134-input can't be a module right now

There are some symbols at saa7134-input that are used on saa7134
and vice-versa. Due to that, module install fails.

So, partially revert commit 9f495cf7d691c99bf7bdcec9f35fcfdad2cf9ae9.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>