Implement migrate_pages syscall decoder

* linux/dummy.h (sys_migrate_pages): Remove.
* linux/syscall.h (sys_migrate_pages): New prototype.
* mem.c (sys_migrate_pages): New function.
diff --git a/mem.c b/mem.c
index 6432a35..88b3a2b 100644
--- a/mem.c
+++ b/mem.c
@@ -829,6 +829,18 @@
 }
 
 int
+sys_migrate_pages(struct tcb *tcp)
+{
+	if (entering(tcp)) {
+		tprintf("%ld, ", (long) (pid_t) tcp->u_arg[0]);
+		get_nodes(tcp, tcp->u_arg[2], tcp->u_arg[1], 0);
+		tprints(", ");
+		get_nodes(tcp, tcp->u_arg[3], tcp->u_arg[1], 0);
+	}
+	return 0;
+}
+
+int
 sys_move_pages(struct tcb *tcp)
 {
 	if (entering(tcp)) {