V4L/DVB: V4L: do not autoselect components on embedded systems

Tuner, DVB frontend and video helper chip drivers are by default
autoselected by their respective host cards, this, however, doesn't make
much sense on SoC-based systems. Disable autoselection on EMBEDDED
systems.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>