media: cx25840: add pin to pad mapping and output format configuration

This commit adds pin to pad mapping and output format configuration support
in CX2584x-series chips to cx25840 driver.

This functionality is then used to allow disabling ivtv-specific hacks and
configuration values (called a "generic mode"), so cx25840 driver can be
used for other devices not needing them without risking compatibility
problems.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>