Increment the DMA counter if gralloc_alloc completes successfully

There was "delete cb" without decrementing the DMA counter which
could lead to a leak.

Bug: 128324105
Test: make
Change-Id: I7307c133a84132e76648fbfe1e60e49a5ef477dc
Signed-off-by: Roman Kiryanov <rkir@google.com>
1 file changed