net: marvell10g: report firmware version

Report the firmware version when probing the PHY to allow issues
attributable to firmware to be diagnosed.

Tested-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>