drm/i915 fixes for v5.6-rc3: - Workaround missing Display Stream Compression (DSC) state readout by forcing modeset when its enabled at probe - Fix EHL port clock voltage level requirements - Fix queuing retire workers on the virtual engine - Fix use of partially initialized waiters - Stop using drm_pci_alloc/drm_pci/free - Fix rewind of RING_TAIL by forcing a context reload - Fix locking on resetting ring->head - Propagate our bug filing URL change to stable kernels