net: mvpp2: reconfiguring the port interface is PPv2.2 specific

This patch adds a check on the PPv2 version in-use not to reconfigure
the port mode when an interface is updated when using PPv2.1 as the
functions called are PPv2.2 specific.

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>