drm/imagination: Numerous documentation fixes.

Some reported by Stephen Rothwell. The rest were found by running the
kernel-doc build script.
Some indentation fixes.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311241526.Y2WZeUau-lkp@intel.com/
Signed-off-by: Donald Robson <donald.robson@imgtec.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231128173507.95119-1-donald.robson@imgtec.com

drm/imagination: Implement free list and HWRT create and destroy ioctls

Implement ioctls to create and destroy free lists and HWRT datasets. Free
lists are used for GPU-side memory allocation during geometry processing.
HWRT datasets are the FW-side structures representing render targets.

Changes since v8:
- Corrected license identifiers

Changes since v6:
- Fix out-of-bounds shift in get_cr_multisamplectl_val()

Changes since v4:
- Remove use of drm_gem_shmem_get_pages()

Changes since v3:
- Support free list grow requests from FW
- Use drm_dev_{enter,exit}

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/919358c5887a7628da588c455a5bb7e3ea4b47ae.1700668843.git.donald.robson@imgtec.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>