[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/include/uapi/asm/unistd.h b/arch/ia64/include/uapi/asm/unistd.h
index 9038726..762edce 100644
--- a/arch/ia64/include/uapi/asm/unistd.h
+++ b/arch/ia64/include/uapi/asm/unistd.h
@@ -335,5 +335,6 @@
 #define __NR_userfaultfd		1343
 #define __NR_membarrier			1344
 #define __NR_kcmp			1345
+#define __NR_mlock2			1346
 
 #endif /* _UAPI_ASM_IA64_UNISTD_H */