clk: qcom: clk-debug: Fixes to the debug measurement logic

Certain debug measurement paths have dividers that need to be
accommodated in the clock rate measurement. Add logic for this.

Not all recursive muxes have a debug clock associated with
them. Add a check for it.

Make corrections to the mask logic.

Change-Id: Ia5db4ec2fbb9bfcdfbdd7aab2956930b6ffa6f24
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>