msm: camera: utils: Add APIs for clock round rate, set flags

Add utility functions to facilitate clients to get
rounded clock rate for the given clock's rate and
to set clock flags.

Change-Id: If65051d6de9a1320fbd2ca9c902afac3c6063da5
Signed-off-by: Pavan Kumar Chilamkurthi <pchilamk@codeaurora.org>