Revert "msm: msm_fb: Fix Regressions because of overmap changes."

This reverts commit 40d83c037cbe0263ebfa20332aa55b8eeb7e1f53.
Revert "msm: msm_fb: Map RGB layers to the max possible size."

This reverts commit f0723ccf455eeb598afb289b8e562f2fb2f28bab.