ARM: dts: msm: Add linux,contiguous-region for 8x74 PIL regions

PIL is now being migrated from Ion to using CMA regions. Add
the phandle reference to the CMA regions for later use. This has
no effect until dma_alloc is called.

Change-Id: Ib40ffda7b905af41a98c1101a8a2b0526956472e
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>