ALSA: opl3sa2: replace nd_opl3sa2_info_xxx() with snd_wss_info_xxx()

Replace snd_opl3sa2_info_xxx() with snd_wss_info_xxx().
Drop check of card->private_data which cannot be NULL
if card is not NULL (spotted by Rene Herman).

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Reviewed-by: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>