Change atomics in ashmem from uint64_t to uint32_t

Fix: 117849512

Test: Blueline: atest AHardwareBufferTest BufferHub_test
 buffer_hub_queue_producer-test libgui_test
libsensor_test vrflinger_test buffer_hub-test buffer_hub_queue-test
dvr_buffer_queue-test dvr_api-test dvr_display-test
Test: in libui_test InputSurfacesTest are segfault on top of master already.

Test: Vega: AHardwareBufferTest BufferHubBuffer_test
BufferHubMetadata_test buffer_hub_queue_producer-test buffer_hub-test
dvr_buffer_queue-test buffer_hub_queue-test dvr_api-test
libdvrtracking-test

Change-Id: I55f91c21f7ac07615b5451b5413521d7938cf591