gc: print of unsafe.Pointer

Got lost when I introduced TUNSAFEPTR.

R=ken2
CC=golang-dev
https://golang.org/cl/4442046

src/cmd/gc/walk.c

@@ -1785,7 +1785,7 @@ walkprint(Node *nn, NodeList **init, int defer)
 					on = syslook("printiface", 1);
 				argtype(on, n->type);		// any-1
 			}
-		} else if(isptr[et] || et == TCHAN || et == TMAP || et == TFUNC) {
+		} else if(isptr[et] || et == TCHAN || et == TMAP || et == TFUNC || et == TUNSAFEPTR) {
 			if(defer) {
 				fmtprint(&fmt, "%%p");
 			} else {

test/fixedbugs/bug328.go

+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import "unsafe"
+
+func main() {
+	var p unsafe.Pointer
+	println(p)
+}

test/golden.out

@@ -157,6 +157,9 @@ panic: interface conversion: interface is int, not int32
 panic: interface conversion: interface is main.T, not main.T
 
 
+=========== fixedbugs/bug328.go
+0x0
+
 == bugs/
 
 =========== bugs/bug322.go