sunxi-mali-mainline: new package

sunxi-mali-mainline: new package

Add Allwinner Mali openGL userspace driver r6p2.
Used combined with kernelspace Mali driver,
it gives possibility to use 3D openGL SoC acceleration.
It provides fbdev libraries and headers.
It is compatible with Linux >= 4.4 as sunxi-mali-driver-mainline.

[Peter: Move version logic to Config.in, ensure directories exists]
Signed-off-by: Giulio Benetti <giulio.benetti@micronovasrl.com>
Reviewed-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>