drm/ci: rockchip: add tests for rockchip display driver

For rockchip rk3288 and rk3399, the display driver is rockchip
and gpu driver is panfrost. Currently, in drm-ci for rockchip
rk3288 and rk3399, only the gpu driver is tested. Refactor
the existing rockchip jobs to test both display and gpu driver
and update xfails.

Since the correct driver name is passed from the job to test gpu
and display driver, remove the check to set IGT_FORCE_DRIVER
based on driver name for rockchip jobs.

Signed-off-by: Vignesh Raman <vignesh.raman@collabora.com>