[ALSA] Dreamcast AICA sound - Get rid of annoying compiler warning

This patch supresses an annoying compiler warning that the variable
err may be used uninitialised.
Signed-off by: Adrian McMenamin <adrian@mcmen.demon.co.uk>

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>