Fix overlapping memcpy areas in impeg2_mc_fullx_fully_8x8 am: 7a56a9f0d1

Original change: https://android-review.googlesource.com/c/platform/external/libmpeg2/+/2132593

Change-Id: I11cf992698dd8025ad7c177d5dbf3c6f29d1a7bf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>