Garbage collect pc98-only variables still referenced in sys/modules/Makefile

These should have been removed with r312910

sys/modules/Makefile

@@ -64,8 +64,6 @@ SUBDIR=	\
 	bwn_pci \
 	${_bytgpio} \
 	cam \
-	${_canbepm} \
-	${_canbus} \
 	${_cardbus} \
 	${_carp} \
 	cas \
@@ -91,7 +89,6 @@ SUBDIR=	\
 	${_crypto} \
 	${_cryptodev} \
 	${_cs} \
-	${_ct} \
 	${_ctau} \
 	ctl \
 	${_cxgb} \
@@ -295,7 +292,6 @@ SUBDIR=	\
 	${_pflog} \
 	${_pfsync} \
 	plip \
-	${_pmc} \
 	${_pms} \
 	ppbus \
 	ppc \
@@ -344,7 +340,6 @@ SUBDIR=	\
 	sk \
 	smbfs \
 	sn \
-	${_snc} \
 	snp \
 	sound \
 	${_speaker} \