clk: qcom: clk-debug: Detach the clock request from syscon regmap

syscon_regmap_lookup_by_phandle prepares the 0th clk handle provided in
the device node. The debug clock controller prepares/enables/disables the
required clock, thus it is safe to detach the clock to remove the
undesired clock prepare votes.

Change-Id: Ibacac8161ba8244c170a87f172c3ad9029625ed7
Signed-off-by: Taniya Das <tdas@codeaurora.org>