ARM: Add definition for monitor mode

<asm/ptrace.h> provides *_MODE definitions for the various processor
modes, but monitor mode was missing.

Add MON_MODE to avoid code using the hardcoded value.

Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
ARM maintainers: Please provide your ack, as this is a dependency for a
mach-shmobile patch.

v3:
  - No changes,

v2:
  - New.
diff --git a/arch/arm/include/uapi/asm/ptrace.h b/arch/arm/include/uapi/asm/ptrace.h
index 5af0ed1..70ff6bf 100644
--- a/arch/arm/include/uapi/asm/ptrace.h
+++ b/arch/arm/include/uapi/asm/ptrace.h
@@ -53,6 +53,7 @@
 #endif
 #define FIQ_MODE	0x00000011
 #define IRQ_MODE	0x00000012
+#define MON_MODE	0x00000016
 #define ABT_MODE	0x00000017
 #define HYP_MODE	0x0000001a
 #define UND_MODE	0x0000001b