CONFIG_SOUND_WM97XX: remove stale makefile line

The driver is gone for a long time.
Reported-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sound/oss/Makefile

@@ -31,8 +31,6 @@ obj-$(CONFIG_SOUND_VWSND)	+= vwsnd.o
 obj-$(CONFIG_SOUND_AU1550_AC97)	+= au1550_ac97.o ac97_codec.o
 obj-$(CONFIG_SOUND_BCM_CS4297A)	+= swarm_cs4297a.o
 
-obj-$(CONFIG_SOUND_WM97XX)	+= ac97_plugin_wm97xx.o
-
 obj-$(CONFIG_DMASOUND)		+= dmasound/
 
 # Declare multi-part drivers.