[media] coda: export auxiliary buffers via debugfs

This patch exports all auxiliary buffers, including SRAM, as debugfs binary
blobs for debugging purposes. It shows, for example, that psbuf currently
doesn't seem to be used at all on CODA7541, and that slicebuf and workbuf
usage is far from the maximum. It can also be used to validate SRAM size
allocation.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>