ALSA: opti93x: fix irq releasing if the irq cannot be allocated

Use the chip->irq to check if the irq should be released so the irq is not released
if it has not been allocated.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>