V4L/DVB (5152): Implements VIDIOC_[S|G]_INPUT on radio-aztech/radio-maxiradio

fmtools use VIDIOCSTUNER, with, in turn, calls VIDIOC_S_INPUT on v4l1-compat.
So, those ioctls are required for V4L1  to work properly.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>