staging: android: ion: ion_cma_heap.c: Fix checkpatch warning

This patch fix coding style:

- Remove "fail memory allocation" waring
- Remove return of void function

Tested by compilation only

Signed-off-by: Phong Tran <tranmanphong@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>