Fix interval interrupt of cadence ttc when timer is in decrement mode

The interval interrupt is not set if the timer is in decrement mode.
This is because x >=0 and x < interval after leaving the while-loop.
Signed-off-by: NJohannes Schlatow <schlatow@ida.ing.tu-bs.de>
Message-id: 20150630135821.51f3b4fd@johanness-latitude
Reviewed-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

hw/timer/cadence_ttc.c

@@ -208,15 +208,14 @@ static void cadence_timer_sync(CadenceTimerState *s)
             s->reg_intr |= (2 << i);
         }
     }
+    if ((x < 0) || (x >= interval)) {
+        s->reg_intr |= (s->reg_count & COUNTER_CTRL_INT) ?
+            COUNTER_INTR_IV : COUNTER_INTR_OV;
+    }
     while (x < 0) {
         x += interval;
     }
     s->reg_value = (uint32_t)(x % interval);
-
-    if (s->reg_value != x) {
-        s->reg_intr |= (s->reg_count & COUNTER_CTRL_INT) ?
-            COUNTER_INTR_IV : COUNTER_INTR_OV;
-    }
     cadence_timer_update(s);
 }