clk: qcom: sdm660: Add support for RPM controlled clocks

Add the SMD-RPM clock which are required by clients to
be voted on sdm660.
This is snapshot of the SMD-RPM clock driver as of
msm-4.14 'commit 4d7da9f5ed3ac19c8 (" Merge "defconfig:
sa8195: Enable config for dyn splash"")'.

Change-Id: Iaff7dfaf1c8ae3c7ff0469ae3dcbf8be2de49304
Signed-off-by: Taniya Das <tdas@codeaurora.org>