ALSA: pcmtest: Add 'open' PCM callback error injection

Extend 'pcmtest' virtual driver with 'open' callback error injection
functionality, as it already can inject errors into other PCM callbacks.
Add module parameter which enables EBUSY error injection in the 'open'
PCM callback.

Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20230713075953.13692-1-ivan.orlov0322@gmail.com


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