net: phy: marvell: implement config_inband() method

Implement the config_inband() method for Marvell 88E1112, 88E1111,
and Finisar's 88E1111 variant.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1tIUrz-006IUO-3r@rmk-PC.armlinux.org.uk


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