clk: qcom: clock-rpm: Add interface to vote for BIMC clock

On some targets, Linux needs to make an explicit vote for the BIMC clock
before registering all the rpm controlled clocks. Add an interface to do
the same.

Change-Id: Ic207575eea09da1e2236182f81999adcff5fa424
Signed-off-by: Pushkar Joshi <pushkarj@codeaurora.org>