include: add SPDX GPL-2.0-only license tags for files without licensing information ...

According to our /README, GPL-2.0-only applies for the whole project
except noted otherwise.

Signed-off-by: Roland Hieber <rohieb@rohieb.name>
Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

of: pci: import of_pci_get_devfn() ...

Marvell MVEBU PCIe driver requires of_pcie_get_devfn(), import it from
Linux.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>