msm/video: add true ARGB

(or named following the MDP convention, reading from LSB to MSB, BGRA)

Mesa EGL and X11 really seem to expect ARGB.  Which is a bit
unfortunate, as android seems to expect ABGR.  At least for now you can
change the default and build a kernel that will make the linux userspace
happy.
Edited flo_defconfig