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

This reverts commit 1603038bd18dc99c503450a3fc204d1978272c78.

Change-Id: I83b3e01bb52d01dd488a17dd48e84b5fead06fc6
Revert "msm: msm_fb: Map RGB layers to the max possible size."

This reverts commit 0d1e8ba6f970ea808e4d7dfed93c71c315488b9e.

Change-Id: I93b3e11bb52d00dd418a17ad48c84151ead06fc6