msm: camera: icp: Keep AHB vote at SVS

The device clocks can change independently of AHB levels. Since the
AHB level does not significantly affect performance, keep it at SVS
and vary the ICP device clocks as required.

Change-Id: I871eaad8cfbd245a7f90d679134c41883e185933
Signed-off-by: Lynus Vaz <lvaz@codeaurora.org>