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/compulab/cm_t335/cm_t335.c b/board/compulab/cm_t335/cm_t335.c
index 592ef3d..428aee6 100644
--- a/board/compulab/cm_t335/cm_t335.c
+++ b/board/compulab/cm_t335/cm_t335.c
@@ -114,7 +114,7 @@
 	if (rv)
 		get_efuse_mac_addr(enetaddr);
 
-	if (!is_valid_ether_addr(enetaddr))
+	if (!is_valid_ethaddr(enetaddr))
 		return -1;
 
 	return eth_setenv_enetaddr("ethaddr", enetaddr);