drm/imagination: Implement job submission and scheduling

Implement job submission ioctl. Job scheduling is implemented using
drm_sched.

Jobs are submitted in a stream format. This is intended to allow the UAPI
data format to be independent of the actual FWIF structures in use, which
vary depending on the GPU in use.

The stream formats are documented at:
https://gitlab.freedesktop.org/mesa/mesa/-/blob/f8d2b42ae65c2f16f36a43e0ae39d288431e4263/src/imagination/csbgen/rogue_kmd_stream.xml

Changes since v8:
- Updated for upstreamed DRM scheduler changes
- Removed workaround code for the pending_list previously being updated
after run_job() returned
- Fixed null deref in pvr_queue_cleanup_fw_context() for bad stream ptr
given to create_context ioctl
- Corrected license identifiers

Changes since v7:
- Updated for v8 "DRM scheduler changes for XE" patchset

Changes since v6:
- Fix fence handling in pvr_sync_signal_array_add()
- Add handling for SUBMIT_JOB_FRAG_CMD_DISABLE_PIXELMERGE flag
- Fix missing dma_resv locking in job submit path

Changes since v5:
- Fix leak in job creation error path

Changes since v4:
- Use a regular workqueue for job scheduling

Changes since v3:
- Support partial render jobs
- Add job timeout handler
- Split sync handling out of job code
- Use drm_dev_{enter,exit}

Changes since v2:
- Use drm_sched for job scheduling

Co-developed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Co-developed-by: Donald Robson <donald.robson@imgtec.com>
Signed-off-by: Donald Robson <donald.robson@imgtec.com>
Signed-off-by: Sarah Walker <sarah.walker@imgtec.com>
Link: https://lore.kernel.org/r/c98dab7a5f5fb891fbed7e4990d19b5d13964365.1700668843.git.donald.robson@imgtec.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>