net: dsa: mv88e6xxx: fix 88E6191 ops

The mv88e6xxx_info structure for the 88E6191 chip was pointing the
mv88e6391_ops definition instead of mv88e6191_ops. Fix this.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>