ALSA: avoid 'bool' as variable name

In modern C versions, 'bool' is a keyword that cannot be used as
a variable name, so change this instance use something else, and
change the type to bool instead.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20240216130211.3828455-1-arnd@kernel.org


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