Add .get_selection() and .set_selection() soc-camera host driver
operations. Additionally check, that the user is not trying to change the
output sizes during a running capture.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>