Kirkwood: Upgated licencing for files imported from linux source to GPLv2 or later

These are few files directly imported from Linux kernel source.
Those are not modifyed at all ar per strategy.
These files contains source with GPLv2 only
whereas u-boot expects GPLv2 or latter

These files are updated for the same from prior permission from original writes

Acked-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Prafulla Wadaskar <prafulla@marvell.com>