gralloc: Back out hacks now that Mali-derping is fixed

Two reverts squashed, due to Mali-derping being fixed
in frameworks/native:

Revert "gralloc: avoid using framebuffer"

This reverts commit 5125ccc5.

Revert "gralloc:  Send first 2 FB buffers to carveout and next to UMP"

This reverts commit d288deb2.

Change-Id: I530dc255b7543e03d0e8277d3ad12ed11d6649ab