allocators: Add DMABuf synchronization

When doing CPU Access, some architecture may require caches to be
synchronize before use. Otherwise, some visual artifact may be
visible, as the CPU modification may still resides in cache.

https://bugzilla.gnome.org/show_bug.cgi?id=794216

BUG: 148221549
Change-Id: I0d54d8368d9ed5855721852493183ee88205929d
3 files changed