[media] adv7842: return 0 if no change in s_dv_timings
[media] adv7842: return 0 if no change in s_dv_timings

Return 0 if the new timings are equal to the current timings as
it caused extra cp-loss/lock interrupts.

Signed-off-by: Martin Bugge <e5d2a331737013ac103e1a31216f68dbca52ec44@cisco.com>
Signed-off-by: Hans Verkuil <3a513708f73c27e7d36ebc496aa41dad6a3153ea@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <0cae1d1e981e84d16b82ca3d17be8a7f826608d3@samsung.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs