sunhme: fix return values from sunhme_receive() during receive packet processing

The current return values in sunhme_receive() when processing incoming packets
are inverted from what they should be. Make sure that we return 0 to indicate
the packet was discarded (and polling is to be disabled) and -1 to indicate
that the packet was discarded but polling for incoming data is to be continued.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

hw/net/sunhme.c

@@ -728,7 +728,7 @@ static ssize_t sunhme_receive(NetClientState *nc, const uint8_t *buf,
 
     /* Do nothing if MAC RX disabled */
     if (!(s->macregs[HME_MACI_RXCFG >> 2] & HME_MAC_RXCFG_ENABLE)) {
-        return -1;
+        return 0;
     }
 
     trace_sunhme_rx_filter_destmac(buf[0], buf[1], buf[2],
@@ -757,14 +757,14 @@ static ssize_t sunhme_receive(NetClientState *nc, const uint8_t *buf,
                 /* Didn't match hash filter */
                 trace_sunhme_rx_filter_hash_nomatch();
                 trace_sunhme_rx_filter_reject();
-                return 0;
+                return -1;
             } else {
                 trace_sunhme_rx_filter_hash_match();
             }
         } else {
             /* Not for us */
             trace_sunhme_rx_filter_reject();
-            return 0;
+            return -1;
         }
     } else {
         trace_sunhme_rx_filter_promisc_match();