IO: Fix bug in DMA Device where receiving a snoop on DMA port would cause a panic.

--HG--
extra : rebase_source : 8152d4fa7d7354c9f150a450ae0710e95141ba4b
diff --git a/src/dev/io_device.cc b/src/dev/io_device.cc
index 5c13b50..dab1f76 100644
--- a/src/dev/io_device.cc
+++ b/src/dev/io_device.cc
@@ -142,13 +142,9 @@
 
         pkt->reinitNacked();
         queueDma(pkt, true);
+    } else if (pkt->isRequest() && recvSnoops) {
+        return true; 
     } else if (pkt->senderState) {
-        if (recvSnoops) {
-            if (pkt->isRequest()) {
-                return true;
-            }
-        }
-
         DmaReqState *state;
         backoffTime >>= 2;