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

GCC/MMSS use XO clock to derive the correct rate of PLLs. cxo_gcc and
cxo_mmss 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/MMSS.

Change-Id: Ieb05897ec93661624dbc842d8619ae40e48c10bc
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>