[IA64] Enable mlock2 syscall for ia64

New system call added in
  commit a8ca5d0ecbdde5cc3d7accacbd69968b0c98764e
  mm: mlock: add new mlock system call

Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index dcd97f8..534a74a 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -1771,5 +1771,6 @@
 	data8 sys_userfaultfd
 	data8 sys_membarrier
 	data8 sys_kcmp				// 1345
+	data8 sys_mlock2
 
 	.org sys_call_table + 8*NR_syscalls	// guard against failures to increase NR_syscalls