ARM: dts: msm: enable SDHCI PM QoS for msm8996

This enables both IRQ and cpu group voting.
Latency values are such that fast power-collapse will be avoided,
while wfi mode is enabled.

Change-Id: I5a8807b662688e420453b7b819cbb5993aec7cb8
Signed-off-by: Gilad Broner <gbroner@codeaurora.org>