Remove rumpuser_yield(). Not only doesn't it really make sense

here, some kind soul made it completely empty.

sys/rump/librump/rumpkern/emul.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: emul.c,v 1.49 2008/09/30 19:25:56 pooka Exp $	*/
+/*	$NetBSD: emul.c,v 1.50 2008/10/02 19:37:23 pooka Exp $	*/
 
 /*
  * Copyright (c) 2007 Antti Kantee.  All Rights Reserved.
@@ -532,14 +532,6 @@ suspendsched()
 	panic("%s: not implemented", __func__);
 }
 
-void
-yield(void)
-{
-
-	rumpuser_yield();
-}
-
-
 u_int
 lwp_unsleep(lwp_t *l, bool cleanup)
 {

sys/rump/librump/rumpkern/misc_stub.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: misc_stub.c,v 1.11 2008/08/01 19:34:51 pooka Exp $	*/
+/*	$NetBSD: misc_stub.c,v 1.12 2008/10/02 19:37:23 pooka Exp $	*/
 
 /*
  * Copyright (c) 2007 Antti Kantee.  All Rights Reserved.
@@ -43,10 +43,22 @@
 int nbpg = 4096;
 #endif
 
+void
+yield(void)
+{
+
+	/*
+	 * Do nothing - doesn't really make sense as we're being
+	 * scheduled anyway.
+	 */
+	return;
+}
+
 void
 preempt()
 {
 
+	/* see yield */
 	return;
 }
 

sys/rump/librump/rumpuser/rumpuser.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: rumpuser.c,v 1.18 2008/07/29 13:17:47 pooka Exp $	*/
+/*	$NetBSD: rumpuser.c,v 1.19 2008/10/02 19:37:23 pooka Exp $	*/
 
 /*
  * Copyright (c) 2007 Antti Kantee.  All Rights Reserved.
@@ -293,12 +293,6 @@ rumpuser_realpath(const char *path, char resolvedname[MAXPATHLEN], int *error)
 	return rv;
 }
 
-void
-rumpuser_yield(void)
-{
-
-}
-
 #ifdef __linux__
 /* eewww */
 size_t strlcpy(char *, const char *, size_t);

sys/rump/librump/rumpuser/rumpuser.h

@@ -1,4 +1,4 @@
-/*	$NetBSD: rumpuser.h,v 1.22 2008/08/08 13:57:59 pooka Exp $	*/
+/*	$NetBSD: rumpuser.h,v 1.23 2008/10/02 19:37:23 pooka Exp $	*/
 
 /*
  * Copyright (c) 2007 Antti Kantee.  All Rights Reserved.
@@ -66,8 +66,6 @@ int rumpuser_gethostname(char *, size_t, int *);
 
 char *rumpuser_realpath(const char *, char *, int *);
 
-void rumpuser_yield(void);
-
 /* rumpuser_pth */
 
 int  rumpuser_thrinit(void);