msm: camera: Fix some shared gpio issues

Do not override the soc private structure, it will
cause kernel panic. Update the ref count logic to
just power on, power down one time. Also, free the
power setting in sensor sub module.

Change-Id: Ife891d393c4c665eca05cff6ea01e64608c14d97
Signed-off-by: Depeng Shao <depengs@codeaurora.org>