arm64: dts: qcom: msm8916: Use fixed factor xo clock

arm64: dts: qcom: msm8916: Use fixed factor xo clock

The rpmcc driver is providing the XO clock, which is the parent of almost
all clocks. But during boot, this driver may probe later and leave most of
the clocks without parent. The common clock framework currently reports
invalid rate for orphan clocks and this may confuse drivers.

To resolve this, use fixed clocks registration until we have some support
to deal with the this issue. Removing the generic rpmcc compatible is
enough to switch back to fixed factor XO clock.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>