net: dsa: mv88e6xxx: Abstract stats_snapshot into ops structure

Taking a stats snapshot differs between same families. Abstract this
into an ops member. At the same time, move the code into global1.[ch],
since the registers are in the global1 range.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h b/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h
index de179c5..7c61cf6 100644
--- a/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h
+++ b/drivers/net/dsa/mv88e6xxx/mv88e6xxx.h
@@ -794,6 +794,11 @@ struct mv88e6xxx_ops {
 	 * Use SPEED_UNFORCED for normal detection, SPEED_MAX for max value.
 	 */
 	int (*port_set_speed)(struct mv88e6xxx_chip *chip, int port, int speed);
+
+	/* Snapshot the statistics for a port. The statistics can then
+	 * be read back a leisure but still with a consistent view.
+	 */
+	int (*stats_snapshot)(struct mv88e6xxx_chip *chip, int port);
 };
 
 enum stat_type {