net: mvpp2: set xlg flow control in mvpp2_mac_link_up()

Set the flow control settings in mvpp2_mac_link_up() for 10G links
just as we do for 1G and slower links. This is now the preferred
location.

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