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/include/serial.h b/include/serial.h
index a298a0b..5173499 100644
--- a/include/serial.h
+++ b/include/serial.h
@@ -3,10 +3,9 @@
 
 #include <post.h>
 
-#define NAMESIZE 16
-
 struct serial_device {
-	char name[NAMESIZE];
+	/* enough bytes to match alignment of following func pointer */
+	char name[16];
 
 	int  (*init) (void);
 	int  (*uninit) (void);