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: 0417715 ("ALSA: compress_offload: introduce accel operation mode")
Reported-by: Stephen Rothwell <[email protected]>
Closes: https://lore.kernel.org/linux-next/[email protected]/
Signed-off-by: Bagas Sanjaya <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>

Author: bagasme

Documentation/sound/designs/compress-accel.rst

@@ -57,7 +57,7 @@ from the input buffer size).
 State Machine
 =============
 
-The passthrough audio stream state machine is described below :
+The passthrough audio stream state machine is described below::
 
                                        +----------+
                                        |          |