clk: qcom: Remove support for gpu throttle xo clock

The support for GPU throttle XO clock was removed as part of
'2c7b087e("clk: qcom: gcc: Remove GPU throttle XO clock for Bengal")'.
So remove support from DebugCC also.

Change-Id: I282d41cee280b814cf783cf214d9f64832460c0a
Signed-off-by: Taniya Das <tdas@codeaurora.org>