sound: remove reference to dead sound OSS vars AEDSP16_MSS and SBPRO

Remove the Kconfig definitions of unused variables AEDSP16_MSS and
AEDSP16_SBPRO since they're:

1) unused, and
2) referenced incorrectly anyway.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>