msm: camera: Fix camera devices disable sequence

Ensure clocks are turned off after tasklet is kill
and device is not in active state. This is to
prevent bus lockdown if the device is accessing
the bus and clock is turn off
Also ensure clocks are on, when accessing hardware
registers.

Change-Id: I4010b96709f48b8cf2bf532e57442152f2e30de9
Signed-off-by: Kevin Chan <ktchan@codeaurora.org>