ARM: dts: msm: Setup PIL memory for the Venus and ADSP

To allow relocatable images for the Venus and ADSP
to be loaded by the PIL driver, add an ION heap
that uses the peripheral_mem memory node.

Also add the linux,contiguous-region property to
account for future migration to the dma APIs in
the PIL driver.

Change-Id: Id899ee9ccbea6676436b151c16c9a3eeab5307d8
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>