Revert "[ARM] msm: fix mdp_off"

Preserve original mdp off sequence to remove DMA failure.  Previously the power
off sequence was modified to resolve display turn on / off issue, but the
changes is not necessary in current kernel and just causes side effects
resulting in fb_blank being stuck due to occasional DMA failures.

Change-Id: Iad57ab0bd77b7dca06d2198437cbe3cb715353d7