media: rkvdec: Add RCB and SRAM support

media: rkvdec: Add RCB and SRAM support

The RCB (Rows and Cols Buffers) are a set of buffers used by other
variations of the decoder to store temporary data.

Those variation come with a dedicated SRAM area used to store those
buffers for better performances.

The buffer sizes are either the width or height of the frame being
decoded multiplied by a documented factor and can be stored either
in SRAM or RAM.
A fallback to RAM is provided if the SRAM is full (e.g.: multiple
streams are being decoded at the same time).

To manage the different kind of allocation, an enum is added to the
rkvdec_aux_buf struct to specify how the buffer was allocated, and
so, how to free it.

This commit is in preparation of other variants support.

Tested-by: Diederik de Haas <didi.debian@cknow.org>  # Rock 5B
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>