net: phy: marvell10g: rename register

The MV_V2_PORT_MAC_TYPE_* is part of the CTRL register. Rename to
MV_V2_PORT_CTRL_MACTYPE_*.

Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>