display: Don't use MDP flip if prerotation is disabled

Change I7fd18226d8337b2cd9341d709c2bd030eff881f7 introduced the
flip operations to MDP, but those depend on prerotation. On
devices with disabled prerotation (like the mako), this causes
artifacting (horizontal mirroring) with 180 rotations.

Change-Id: I6f7d03a12a1315d5bdd9c8b32b1f2289274738a5