Rename gpu_mem.o to gpuMem.o am: 440cf722a9 am: 15748e0a12

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/2146977

Change-Id: I2a58d3807ee95d4c82a972745723fe4ea6be55c7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>