hax: Split the exynos4/tegra legacy code paths

They hang up at different places, and require different fixes.
Tested on t3 and e4

Change-Id: I46257a7e9e6b6e093a5cb92eaaaef4bdd0435a12

Conflicts:
	libs/gui/Android.mk
	libs/gui/Surface.cpp
	services/surfaceflinger/DisplayDevice.cpp

Conflicts:
	services/surfaceflinger/DisplayDevice.cpp