igc: Improve address check in igc_del_mac_filter()

igc_add_mac_filter() doesn't allow filters with invalid MAC address to
be added to adapter->mac_table so, in igc_del_mac_filter(), we can early
return if MAC address is invalid. No need to traverse the table.
Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igc/igc_main.c

@@ -2246,7 +2246,7 @@ static int igc_del_mac_filter(struct igc_adapter *adapter, const u8 *addr,
 	int rar_entries = hw->mac.rar_entry_count;
 	int i;
 
-	if (is_zero_ether_addr(addr))
+	if (!is_valid_ether_addr(addr))
 		return -EINVAL;
 
 	/* Search for matching entry in the MAC table based on given address