ARM: dts: msm: Add ipc-spinlock entry for MSM8936

Add the ipc-spinlock entry to facilitate locking between apps and
non-apps processors.

CRs-Fixed: 628655
Change-Id: Id4f168bba650f055942b5e55583bf53e2305b052
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>