msm_mdp: Update header for 4 layer support

Bug: 7626586
Change-Id: I37730470dc09b7a9d6336b1603f87efd98f45e97
Signed-off-by: Iliyan Malchev <malchev@google.com>
Merge branch 'jb-mr1.1-release' of https://android.googlesource.com/platform/bionic into jellybean

Conflicts:
	libc/kernel/common/linux/msm_mdp.h