kselftest/alsa: Fix validation of writes to volatile controls

kselftest/alsa: Fix validation of writes to volatile controls

When validating writes to controls we check that whatever value we wrote
actually appears in the control.  For volatile controls we cannot assume
that this will be the case, the value may be changed at any time
including between our write and read.  Handle this by moving the check
for volatile controls that we currently do for events to a separate
block and just verifying that whatever value we read is valid for the
control.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240614-alsa-selftest-volatile-v1-1-3874f02964b1@kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/20240616073454.16512-5-tiwai@suse.de