net: mvpp2x: Add GPIO configuration support

This patch add GPIO configuration support in mvpp2x driver.
Driver will handle 10G SFP gpio reset and SFP TX disable. GPIO pins should
be set in device tree.

Signed-off-by: Stefan Chulski <stefanc@marvell.com>
Tested-by: iSoC Platform CI <ykjenk@marvell.com>
Reviewed-by: Kostya Porotchkin <kostap@marvell.com>
Reviewed-by: Igal Liberman <igall@marvell.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Stefan Roese <sr@denx.de>