Fix type confusion of dmabuf in aoc driver This change ensures that the struct dma_heap that is passed in the file descriptor via ioctl is created/maintained by aoc. Bug: 313424730 Test: researcher's PoC doesn't print handle Change-Id: I408872a66964bd4d03d3b09794b2eb626028b60b Signed-off-by: Ismael Castro <[email protected]> (cherry picked from commit 7672a4aaa5bb92bc69337942e5fa047e4964ae62)