net: dsa: mv88e6xxx: add port state setter

Add the port STP state setter to the port files.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dsa/mv88e6xxx/port.h b/drivers/net/dsa/mv88e6xxx/port.h
index ae1ae2b..ac13988 100644
--- a/drivers/net/dsa/mv88e6xxx/port.h
+++ b/drivers/net/dsa/mv88e6xxx/port.h
@@ -21,4 +21,6 @@ int mv88e6xxx_port_read(struct mv88e6xxx_chip *chip, int port, int reg,
 int mv88e6xxx_port_write(struct mv88e6xxx_chip *chip, int port, int reg,
 			 u16 val);
 
+int mv88e6xxx_port_set_state(struct mv88e6xxx_chip *chip, int port, u8 state);
+
 #endif /* _MV88E6XXX_PORT_H */