uboot-phytec

net: introduce transparent driver private in ueth_data

Avoid clutter in ueth_data. Individual drivers should not mess
with structures belonging to the core like this.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Reviewed-by: Marek Vasut <marex@denx.de>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>