Update & cleanup gralloc

Based on https://github.com/CyanogenMod/android_hardware_qcom_display-caf/commit/277b124c636c4bfc891d2481fe939224b93d788e

Signed-off-by: Michael Bestas <mikeioannina@gmail.com>

Change-Id: I57d113ea85270bbe4c7ea1f008393d83a5f40ef7