clk: qcom: clk-debug: Add support for enable mask for debug clk

The enable bit position could vary across targets. Add the
en_mask where the enable bit position could be supplied
for debug clock branch.

Change-Id: I9e910f53e4a13f701a3a37b640c4f72da164f6af
Signed-off-by: Shefali Jain <shefjain@codeaurora.org>