net: cosmetic: Name ethaddr variables consistently

Use "_ethaddr" at the end of variables and drop CamelCase.
Make constant values actually 'const'.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/board/siemens/pxm2/board.c b/board/siemens/pxm2/board.c
index 264ba02..4d8ba3c 100644
--- a/board/siemens/pxm2/board.c
+++ b/board/siemens/pxm2/board.c
@@ -222,7 +222,7 @@
 	struct ctrl_dev *cdev = (struct ctrl_dev *)CTRL_DEVICE_BASE;
 #ifdef CONFIG_FACTORYSET
 	int rv;
-	if (!is_valid_ether_addr(factory_dat.mac))
+	if (!is_valid_ethaddr(factory_dat.mac))
 		printf("Error: no valid mac address\n");
 	else
 		eth_setenv_enetaddr("ethaddr", factory_dat.mac);