ANDROID: staging: ion: make cma heap a module

Add all cma areas that we can find as cma heaps.

Bug: 133508579
Test: build and insmod ion_cma_heap

Change-Id: I3cf1884c8d8914ae31d55e2f2770104347844036
Signed-off-by: Sandeep Patil <sspatil@google.com>