[MIPS] Wire up set_robust_list(2) and get_robust_list(2)

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/scall64-64.S

@@ -466,3 +466,5 @@ sys_call_table:
 	PTR	sys_tee				/* 5265 */
 	PTR	sys_vmsplice
 	PTR	sys_move_pages
+	PTR	sys_set_robust_list
+	PTR	sys_get_robust_list