net/miiphy/serial: drop duplicate "NAMESIZE" define

A few subsystems are using the same define "NAMESIZE".  This has been
working so far because they define it to the same number.  However, I
want to change the size of eth_device's NAMESIZE, so rather than tweak
the define names, simply drop references to it.  Almost no one does,
and the handful that do can easily be changed to a sizeof().

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/drivers/net/mvgbe.c b/drivers/net/mvgbe.c
index 1dcb700..477bf5c 100644
--- a/drivers/net/mvgbe.c
+++ b/drivers/net/mvgbe.c
@@ -702,7 +702,7 @@
 
 		dev = &dmvgbe->dev;
 
-		/* must be less than NAMESIZE (16) */
+		/* must be less than sizeof(dev->name) */
 		sprintf(dev->name, "egiga%d", devnum);
 
 		switch (devnum) {