ARM: dts: msm: power collapse UFS during system suspend on msm8994

UFS host controller on msm8994 supports the core power collapse feature
to reduce the controller leakage current during low power mode.
Power collapse requires reinitialization of the UFS link (between host and
device) after coming out of power collapse, which is a time consuming
operation. To prevent impact on the UFS requests latencies, we will power
collapse UFS controller only during system suspend.
Choosing the spm-level to 5 should enable the UFS core power colalpse
during system suspend.

Change-Id: I42e6d25e189f98acc3eff89ac9e69e0465ce887d
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>