staging: android: ion: Add support for secure CMA allocations in ion_alloc

Add support in ion_alloc for for allocations of type ION_HEAP_TYPE_HYP_CMA
as this is required for certain secure camera use cases.

Change-Id: I7d1a538bb63431b59c1f5995a1d0ceb76207528c
Signed-off-by: Liam Mark <lmark@codeaurora.org>