Add a register dump file in debugfs for some of the buffer-related registers for the main path in MI (for the base address, the size, and the offset). Also dump the corresponding shadow registers. Signed-off-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Dafna Hirschfeld <dafna@fastmail.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>