android: ion: push cma heap to kmemleak_ignore

android: ion: push cma heap to kmemleak_ignore

A reserved memory allocated by memblock is traceable by kmemleak. It
also applies to CMA areas. But CMA areas are different from other
reserved memories. They are unreserved after the kmem is initialized.
It means that the pages in CMA areas are not allocated/reserved once
all pages in CMA areas are returned to the kernel page allocator.
Therefore a reserved memory to be a CMA area should be ignored by
kmemleak.

Change-Id: I17c6511bb2b9ad1279821092fe8ba1a0d0a63e6b
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>