kselftest/alsa: pcm - Add more coverage by default

Add more coverage to our standard test cases:

 - 8kHz mono and stereo to verify that the most common mono format is
   clocked correctly.
 - 44.1kHz stereo to verify that this different clock base is generated
   accurately.
 - 48kHz 6 channel to verify that 6 channel is clocked correctly.
 - 96kHz stereo since that is a common audiophile rate.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221208-alsa-pcm-test-hacks-v4-7-5a152e65b1e1@kernel.org


Signed-off-by: Takashi Iwai <tiwai@suse.de>