ARM: dts: msm: do not disable gpu_cx_gdsc for SM8150

Modify the configurations for gpu_cx_gdsc so that application
processor software does not attempt to disable it.  This GDSC
will instead be disabled by the always-on processor when entering
system sleep.  The AOP also performs a special reset sequence for
the GDSC upon resuming from system sleep.  These steps ensure
that software does not encounter a NOC error when enabling the
GDSC.

Change-Id: I4477ce6016734ea5be66f66e220a5519b4f013b1
Signed-off-by: David Collins <collinsd@codeaurora.org>