media: video: tegra: tegra_camera: re-arch power and clock

There are a couple of issues found in tegra_camera.

1. clock enable/disable is controlled by user space.
   -> If client process crashes, there is no way to disable clock.
2. power enable/disable is associated with clock enable.
   -> There is no reason to relate power with clock.
   -> There is only one regulator for this driver.
   -> As same as #1, it may leave power up when client process crashes.
3. driver allows multiple clients to access.
   -> This is not the case for this driver.

This changes addresses the problems described above.

Bug 948780

Change-Id: Ie534771327175f56cf0e138f1c07096ddba470a8
Signed-off-by: Jihoon Bang <[email protected]>
Reviewed-on: http://git-master/r/92386
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: David Schalig <[email protected]>
Reviewed-by: Dan Willemsen <[email protected]>