display: Fix support for MDP 4.1

 * MDP 4.1 still does not support the borderfill pipe, baselayer logic
   should not be used.

Change-Id: I587bdff4a03ced141e43819eea70cec1aedaeb7b
overlay: Bring back debug.mdpcomp.maxlayer

 * We're having underrun issues with 4-layer composition. It generally
   works, but when the system CPU ramps down and the device is mostly
   idle, underrun is happening.
 * Limiting to 3 layers solves the problem temporarily on these devices.
 * Readd the option so that the issue can be debugged without afflicting
   our current users with massive amounts of flickering.

Change-Id: I7ab7d013f65eaf12a3d21a91229dcaad6a815069
Merge remote-tracking branch 'caf/kk_2.7_rb1.37' into HEAD

Change-Id: Ib84ec7968aae1c3c963d1230c89c16f24ae291ba
display: Properly handle NO_IOMMU case

 * Enable it by default for msm8660 too.

Change-Id: Icbd5de1e7f020285ff6101c34286ca8863b11040
overlay: Allocate from MM heap as a fallback

 * Not all devices support IOMMU yet, so use the MM heap as a fallback.
 * Enabled when NO_IOMMU is set

Change-Id: I9d9f3dffb92f5b4bf45422df0f66a40611943202
display: Cover NO_IOMMU for msm7x30 too

Change-Id: Ic68672f386a06fd0ac9fd1f18eec3188415a8642
display: Various cleanups, fix legacy camera heap

 * Add explicit support for camera heap, if requested
 * Bring in line with kk_2.7
 * Don't push to MM heap for NO_IOMMU for display buffers

Change-Id: I30a8280099aa82e9b3e9754a4a68ad6a81f705f7
libgralloc: Fix mismerge

Commit bde70bd2138b422f86d4c947649a14e909c9e391 was not merged properly

Change-Id: Iee99137a16dcea01f5eb0ede2b9e01f4bccf2940
Add msm8660 as a valid target

Change-Id: Ic19c24428ef5d9ca911e3d8f82b001d61a9377b8
liboverlay: do not return error if fb num >= 2 doesn't exist (writeback).

Some devices doesn't have writeback support, but needs HDMI (fb1)
This will allow them not to break HDMI support.
This is a cleaner implementation as it won't change handling on
8660 devices having writeback (if those exists).

Change-Id: I6c09759dfa4f2b1734f85012cab4eb4f350820ea