clk: qcom: cmn-pll: Add new clock ops for prepare/unprepare

The clocks required to be prepared/unprepared in their corresponding clock
ops before enable/disable of common pll block dependencies.

Change-Id: I1bab6eb9ccb49df4287bec79914d36158b73eb36
Signed-off-by: Taniya Das <tdas@codeaurora.org>