Revert "Revert "Merge omapzoom-changes into drivers/video/omap2/dss/dispc.c""

Reverting this caused graphical artifacts. Bring back the sync to
omapzoom and leave only a problematic piece disabled which can lead
to kernel panics.

This mostly reverts commit 780543728d90e3d972e2b8261c6af131b30b92c0.

Change-Id: If01cc1d5f21ad6b90ddc597ebd5341bcf70e8bb5