Enable USXGMII mode for mv88e6393x chips. Tested on Marvell 88E6191X.
Signed-off-by: Michal Smulski <michal.smulski@ooma.com>
Link: https://lore.kernel.org/r/20230605174442.12493-1-msmulski2@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>