allow forcing HighEndGfx mode

people have already started fipping the lomRam prop to enable
transparent status bar, this will enable it with fewer
repercussions

Change-Id: Ied6de65276425fa1e7db0bf9da35f1932a355172
systemui: improve DessertCaseDream immersive mode exit

Change-Id: I9d68e3f2e63467ae2f842a99e0071b562dfb6b15
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>