ARM: dts: msm: Update 8939 PM with latest recommendation

Modify the L2 SPM DLY register and SPM sequence with latest
commands.
Remove PMIC wait command from CPU7 SPM sequence it is not needed.
Enable RPM handshake in CCI PC sequence.
Update the latency number with latest A53 measurements.
Make the size of debug counters to support 8 cores.

Change-Id: I2cbde8c816d49fdc958ea6e9524574a083256cd6
Signed-off-by: Venkat Devarasetty <vdevaras@codeaurora.org>