[intel] Add missing iounmap()

Reported-by: Thomas Miletich <thomas.miletich@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/intel.c

  err_fetch_mac:
 	intel_reset ( intel );
  err_reset:
+	iounmap ( intel->regs );
 	netdev_nullify ( netdev );
 	netdev_put ( netdev );
  err_alloc:
 	intel_reset ( intel );
 
 	/* Free network device */
+	iounmap ( intel->regs );
 	netdev_nullify ( netdev );
 	netdev_put ( netdev );
 }