Mesa pipe driver for rockchip

Created by: mmind

While based on the sun4i, exynos, meson pipe drivers, I tried to already get infrastructure in place for different gpu types to hook into the rockchip drm later on. I'm still hoping to get my hands on a device with the Rockchip soc using a Vivante gpu :-) Only rockchip-drm-winsys.c differs from the others though.

Tested on a rk3036-kylin board up to 1920x1080 ... and will most likely also work on rk3328 with Mali450 when taking into account the issue with higher resolutions. But I can only confirm that case tomorrow evening.