net: broadcom: bcm4908_enet: fix NAPI poll returned value

Missing increment was resulting in poll function always returning 0
instead of amount of processed packets.

Fixes: 4feffead ("net: broadcom: bcm4908enet: add BCM4908 controller driver")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210224151842.2419-2-zajec5@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/broadcom/bcm4908_enet.c

@@ -583,6 +583,8 @@ static int bcm4908_enet_poll(struct napi_struct *napi, int weight)
 
 		enet->netdev->stats.rx_packets++;
 		enet->netdev->stats.rx_bytes += len;
+
+		handled++;
 	}
 
 	if (handled < weight) {