This commit adds support for changing MTU for the ocelot register based
interface. For ocelot, JUMBO frame size can be set up to 25000 bytes
but has been set to 9000 which is a saner value and allows for maximum
gain of performance with FDMA.
Reviewed-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: NClément Léger <clement.leger@bootlin.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>