msm: camera: Adding interface for power operations in actuator driver

Support for actuator power operation.
- add vreg data parsing from property.
- add interface for power up and down.

Change-Id: I809e23e27d119635e85b565fa6ea2f045b2afdc1
Signed-off-by: Evgeniy Borisov <eborisov@codeaurora.org>