Initialize thread0.td_contested in init_turnstiles() rather than

mutex_init() as it is used by the turnstile code and is not mutex-specific.

sys/kern/kern_mutex.c

@@ -904,9 +904,6 @@ void
 mutex_init(void)
 {
 
-	/* Setup thread0 so that mutexes work. */
-	LIST_INIT(&thread0.td_contested);
-
 	/* Setup turnstiles so that sleep mutexes work. */
 	init_turnstiles();
 

sys/kern/subr_turnstile.c

@@ -328,6 +328,7 @@ init_turnstiles(void)
 		    NULL, MTX_SPIN);
 	}
 	mtx_init(&td_contested_lock, "td_contested", NULL, MTX_SPIN);
+	LIST_INIT(&thread0.td_contested);
 	thread0.td_turnstile = NULL;
 }