msm: clock-debug: Allow dividers between clocks and measurement logic

Some debug implementations output a divided clock specifically
for the measurement circuitry; therefore the measured output
is an integer fraction of the original clock rate. Account for
this by dividing the rate on the clock being measured by the
rate set on the parent of the measure clock.

Change-Id: I07e791670ccfb3eaa29eab76cdbd2bfabce62a38
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>