net: qed: correct existing SPDX tags

QLogic QED drivers source code is dual licensed under
GPL-2.0/BSD-3-Clause.
Correct already existing but wrong SPDX tags to match the actual
license.

Signed-off-by: Alexander Lobakin <alobakin@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>