net: mvpp2: add xlg pcs inband capabilities

Add PCS inband capabilities for XLG in the Marvell PP2 driver, so
phylink knows that 5G and 10G speeds have no inband capabilities.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Daniel Golle <daniel@makrotopia.org>
Link: https://patch.msgid.link/E1uslR9-00000001OxL-44CD@rmk-PC.armlinux.org.uk


Signed-off-by: Jakub Kicinski <kuba@kernel.org>