remove vop_lookup_pre and vop_lookup_post

Suggested by:	kib
MFC after:	5 days

sys/kern/vfs_subr.c

@@ -4094,16 +4094,6 @@ vop_strategy_pre(void *ap)
 #endif
 }
 
-void
-vop_lookup_pre(void *ap)
-{
-}
-
-void
-vop_lookup_post(void *ap, int rc)
-{
-}
-
 void
 vop_lock_pre(void *ap)
 {

sys/kern/vnode_if.src

@@ -65,8 +65,6 @@ vop_islocked {
 
 %% lookup	dvp	L L L
 %% lookup	vpp	- L -
-%! lookup	pre	vop_lookup_pre
-%! lookup	post	vop_lookup_post
 
 # XXX - the lookup locking protocol defies simple description and depends
 #	on the flags and operation fields in the (cnp) structure.  Note