igb: Use irq_synchronize per vector when using MSI-X

Synchronize all IRQs when using MSI-X. Similar to ixgbe.
Issue was reported on e1000e, but the patch is also valid for igb.

CC: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index 667b527..df5dcd2 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -1290,7 +1290,13 @@
 	wr32(E1000_IAM, 0);
 	wr32(E1000_IMC, ~0);
 	wrfl();
-	synchronize_irq(adapter->pdev->irq);
+	if (adapter->msix_entries) {
+		int i;
+		for (i = 0; i < adapter->num_q_vectors; i++)
+			synchronize_irq(adapter->msix_entries[i].vector);
+	} else {
+		synchronize_irq(adapter->pdev->irq);
+	}
 }
 
 /**