ARM: dts: msm: Split system low power mode state id for sdxpoorwills

Sdxpoorwills has a unique architecture different from the rest of the
QTI SoCs using the RPMH architecture. It has as single CPU in a cluster.
The cluster is capable of entering system power states when Linux
chooses the system idle state determined by the available sleep times.
To differenciate between a standlone CPU power off and a system off,
split the PSCI state id between the CPU state and the cluster state.

Change-Id: If0737dc02f3142357f5e08ae876c5cb679119e25
Signed-off-by: Lina Iyer <ilina@codeaurora.org>