ARM: dts: msm: Add audio ION heap for APQ8084

Add audio ION heap to the device tree for APQ8084 target. This heap
is used when audio is executed without SMMU (by-pass mode) enabled.

Change-Id: I7caf81fc170cbb2d6ccc260554ebc46a9ce1412c
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>