msm: camera: ope: Fix OPE clock issue

Due to non-availability of all clock levels, while downgrading
or upgrading the clock rate, ope is voting for zero clock rate.
Fix issue by voting for nearest non-zero clockrate while
upgrading or downgrading the clock rate.

CRs-Fixed: 2649906
Change-Id: I2f3488084e0aa32ecfa84bcbebad887a1ef8409d
Signed-off-by: Rishabh Jain <risjai@codeaurora.org>