Make use of sub-device active state. In most cases the effect on need for
acquiring the mutex is non-existent as access to the driver's core data
structure still needs to be serialised.

This still removes a lot of code as the code paths for active and try
state are the same in many cases.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>