net: mdio: octeon: Select MDIO_DEVRES

This driver makes use of devm_mdiobus_alloc_size. To ensure this is
available select MDIO_DEVRES which provides it.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/mdio/Kconfig

@@ -138,6 +138,7 @@ config MDIO_OCTEON
 	depends on (64BIT && OF_MDIO) || COMPILE_TEST
 	depends on HAS_IOMEM
 	select MDIO_CAVIUM
+	select MDIO_DEVRES
 	help
 	  This module provides a driver for the Octeon and ThunderX MDIO
 	  buses. It is required by the Octeon and ThunderX ethernet device