gralloc: Use compile time flag for mdss.

The gralloc allocation can happen from processes other than
surfaceflinger in which case we cannot open the framebuffer
device to get the mdp version. Use the MDSS_TARGET flag to
differentiate.

Change-Id: I69bc9ff6004b382a2836274a32fbbd3b2e67dea2
overlay: Add tolerance to downscale factor

In certain corner cases for 1080p panels, round doesn't get us
the right downscale factor resulting in MDP attempting to go into
blt mode. Add a tolerance for failure.

Bug: 9322550
Change-Id: I2be4715955d9e248fc63e408dc4a2cdf493152f6
Signed-off-by: Iliyan Malchev <malchev@google.com>
display: Use actual kernel headers for all builds

Change-Id: I1add22c0bc33942bc8f89dbb37333bf08d49bf72
Revert "HWC: Check for proper MDP version to enable C2D comp"

This reverts commit 88e2b9cef6827506467599995e921374ff334ee0.

Change-Id: I092b2c073280b52bd1280fbddbcc09a805800200