clk: qcom: Add support for AOP clock controller

The Always On Processor(AOP) supports enabling,disabling and scaling few
shared clocks using the QMP mailbox client. Add support for the same to
register one such QDSS clock with AOP.

Change-Id: I31dd297acf639640a410494ad4dd96caa76a873f
Signed-off-by: Taniya Das <tdas@codeaurora.org>