ALSA: docs: compress-accel: Format state machine flowchart as code block

ALSA: docs: compress-accel: Format state machine flowchart as code block

Stephen Rothwell reports multiple htmldocs indentation warnings when
merging sound tree for linux-next:

Documentation/sound/designs/compress-accel.rst:67: ERROR: Unexpected indentation.
Documentation/sound/designs/compress-accel.rst:67: WARNING: Blank line required after table.
Documentation/sound/designs/compress-accel.rst:68: WARNING: Line block ends without a blank line.
Documentation/sound/designs/compress-accel.rst:72: WARNING: Block quote ends without a blank line; unexpected unindent.
Documentation/sound/designs/compress-accel.rst:73: WARNING: Block quote ends without a blank line; unexpected unindent.

Fix these above by wrapping passthrough audio stream state machine
flowchart in a literal code block.

Fixes: 04177158cf98 ("ALSA: compress_offload: introduce accel operation mode")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20241028193242.11597640@canb.auug.org.au/
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://patch.msgid.link/20241028111647.17378-2-bagasdotme@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>