msm: pm-8x60: Add SNOC request for faster warmboot

Keep a request of 100 Mhz for SNOC bus when Apps is active. This
improves the exit times from power collapse. Without this change the
trust zone code running in secure mode will be bus limited. The request
will be made one time during bootup, the bus request is active only meaning
when Apps does an RPM notified sleep RPM will remove the SNOC bus request
when transitioning to sleep.

Currently trust zone is not an RPM client so it cannot make this request,
even then it is ineffecient to constantly send RPM SMD messages especially
since standalone power collapse can happen in much greater frequency on
all cores in a multi core processor.

Change-Id: Ief9ccd6c803a9a22c8af350b63f568a33bafa94e
Signed-off-by: Girish Mahadevan <girishm@codeaurora.org>