ARM: msm: dts: Add qchannel property to spm devices for MSM8994v1

On msm8994v1, qchannel should not be ignored when entering power collapse
due to hardware limitations. Add a boolean property, use-qchannel-for-pc,
to the spm node. This property specifies if the qchannel should not be
ignored when entering power collapse.

Change-Id: Ic44e0b8898f8b3d4b33b170aa087969c264fe1ed
Signed-off-by: Karthik Parsha <kparsha@codeaurora.org>