drm/imagination: Add FWIF headers

Changes since v8:
- Corrected license identifiers

Changes since v7:
- Add padding to struct rogue_fwif_ccb_ctl to place read and write offsets
  in different cache lines

Changes since v5:
- Split up header commit due to size
- Add BRN 71242 to device info

Changes since v4:
- Add FW header device info

Signed-off-by: Sarah Walker <sarah.walker@imgtec.com>
Signed-off-by: Donald Robson <donald.robson@imgtec.com>
Acked-by: Maxime Ripard <mripard@kernel.org>