tg3: Fix missed MSI workaround

This patch fixes a minor counter initialization bug and makes the MSI
workaround slightly more efficient by attempting to service pending
interrupts before applying the workaround.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Benjamin Li <benli@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/tg3.c

@@ -8105,7 +8105,7 @@ static void tg3_rings_reset(struct tg3 *tp)
 				tw32_mailbox(tp->napi[i].prodmbox, 0);
 			tw32_rx_mbox(tp->napi[i].consmbox, 0);
 			tw32_mailbox_f(tp->napi[i].int_mbox, 1);
-			tp->napi[0].chk_msi_cnt = 0;
+			tp->napi[i].chk_msi_cnt = 0;
 			tp->napi[i].last_rx_cons = 0;
 			tp->napi[i].last_tx_cons = 0;
 		}
@@ -9185,8 +9185,7 @@ static void tg3_chk_missed_msi(struct tg3 *tp)
 					tnapi->chk_msi_cnt++;
 					return;
 				}
-				tw32_mailbox(tnapi->int_mbox,
-					     tnapi->last_tag << 24);
+				tg3_msi(0, tnapi);
 			}
 		}
 		tnapi->chk_msi_cnt = 0;