i965: Add notification register

This will be used by the wait instruction when implementing the barrier()
function.

v2:
 * Changes suggested by mattst88

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Chris Forbes <chrisf@ijw.co.nz>
Reviewed-by: Matt Turner <mattst88@gmail.com>

src/mesa/drivers/dri/i965/brw_reg.h

@@ -764,6 +764,22 @@ brw_ip_reg(void)
                   WRITEMASK_XYZW); /* NOTE! */
 }
 
+static inline struct brw_reg
+brw_notification_reg(void)
+{
+   return brw_reg(BRW_ARCHITECTURE_REGISTER_FILE,
+                  BRW_ARF_NOTIFICATION_COUNT,
+                  0,
+                  0,
+                  0,
+                  BRW_REGISTER_TYPE_UD,
+                  BRW_VERTICAL_STRIDE_0,
+                  BRW_WIDTH_1,
+                  BRW_HORIZONTAL_STRIDE_0,
+                  BRW_SWIZZLE_XXXX,
+                  WRITEMASK_X);
+}
+
 static inline struct brw_reg
 brw_acc_reg(unsigned width)
 {