Remove copybit MDP_FG_LAYER case
gralloc_priv.h: Add missing definitions
evert "display: Use fences for all targets"

This reverts commit 7961d621773fb9456b441fbd84347e96d031f670.
Revert "Remove copybit MDP_FG_LAYER case"

This reverts commit 11f3216fd1c56ebbbb94ac842ca65871796900cd.