msm_mdp: Update header for 4 layer support

Bug: 7626586
Change-Id: I37730470dc09b7a9d6336b1603f87efd98f45e97
Signed-off-by: Iliyan Malchev <malchev@google.com>
Merge tag 'android-4.2.2_r1' of https://android.googlesource.com/platform/bionic into 1.1

Android 4.2.2 release 1