ARM: dts: qcom: Use correct XO clock for GCC

GCC use XO clock to derive the correct rate of PLLs. cxo_gcc
used previously are dummy voter clocks that have a fixed rate
of 1000. This leads to wrong calculation of PLL rate.
Use the correct XO clock for GCC.

Change-Id: Ib03c27a6447016e349e08c40f4e379c8fd26d69a
Signed-off-by: Taniya Das <tdas@codeaurora.org>