[media] cx24120: More tidying in cx24120_init

Remove reg1 by refactoring for loops
Change ret into an int as it's only used for return values now,
and remove reset_result by using ret instead.

Signed-off-by: Jemma Denson <jdenson@gmail.com>
Signed-off-by: Patrick Boettcher <patrick.boettcher@posteo.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>