net: mvneta: reorder initialisation

Re-order the mvneta initialisation to move devm based resources and
easy setup earlier in the probe function. The primary reason for this
is to allow us to switch the driver to use phylink's mac_select_pcs()
callback.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>