target-or32: Add system instructions

Add OpenRISC system instructions.

Signed-off-by: Jia Liu <proljc@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/target-openrisc/cpu.h b/target-openrisc/cpu.h
index df07eaf..6506665 100644
--- a/target-openrisc/cpu.h
+++ b/target-openrisc/cpu.h
@@ -80,6 +80,9 @@
                                       (reg) |= ((v & 0x1f) << 2);\
                                   } while (0)
 
+/* Version Register */
+#define SPR_VR 0xFFFF003F
+
 /* Internal flags, delay slot flag */
 #define D_FLAG    1