cmd/gc: update hashmap code location in comments

Change-Id: I3b81f2e9eb29ee6349d758b68fe7951b34f15a81
Reviewed-on: https://go-review.googlesource.com/1974Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/gc/walk.c

@@ -706,7 +706,7 @@ walkexpr(Node **np, NodeList **init)
 		walkexpr(&r->right, init);
 		t = r->left->type;
 		p = nil;
-		if(t->type->width <= 128) { // Check ../../runtime/hashmap.c:MAXVALUESIZE before changing.
+		if(t->type->width <= 128) { // Check ../../runtime/hashmap.go:maxValueSize before changing.
 			switch(simsimtype(t->down)) {
 			case TINT32:
 			case TUINT32:
@@ -1101,7 +1101,7 @@ walkexpr(Node **np, NodeList **init)
 
 		t = n->left->type;
 		p = nil;
-		if(t->type->width <= 128) {  // Check ../../runtime/hashmap.c:MAXVALUESIZE before changing.
+		if(t->type->width <= 128) {  // Check ../../runtime/hashmap.go:maxValueSize before changing.
 			switch(simsimtype(t->down)) {
 			case TINT32:
 			case TUINT32: