media: smiapp: Avoid maintaining power state information

Instead of keeping track of the power state ourselves, let runtime PM
handle it.

This also splits handling controls between side effect management and
writing the new configuration to the sensor's registers.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>