dsa: fix 88e6xxx statistics counter snapshotting

The bit that tells us whether a statistics counter snapshot operation
has completed is located in the GLOBAL register block, not in the
GLOBAL2 register block, so fix up mv88e6xxx_stats_wait() to poll the
right register address.
Signed-off-by: Stephane Contri <Stephane.Contri@grassvalley.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/mv88e6xxx.c

@@ -418,7 +418,7 @@ static int mv88e6xxx_stats_wait(struct dsa_switch *ds)
 	int i;
 
 	for (i = 0; i < 10; i++) {
-		ret = REG_READ(REG_GLOBAL2, 0x1d);
+		ret = REG_READ(REG_GLOBAL, 0x1d);
 		if ((ret & 0x8000) == 0)
 			return 0;
 	}