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/gumstix/pepper/board.c b/board/gumstix/pepper/board.c
index f644f81..beb2fac 100644
--- a/board/gumstix/pepper/board.c
+++ b/board/gumstix/pepper/board.c
@@ -165,7 +165,7 @@
 		mac_addr[3] = (mac_hi & 0xFF000000) >> 24;
 		mac_addr[4] = mac_lo & 0xFF;
 		mac_addr[5] = (mac_lo & 0xFF00) >> 8;
-		if (is_valid_ether_addr(mac_addr))
+		if (is_valid_ethaddr(mac_addr))
 			eth_setenv_enetaddr("ethaddr", mac_addr);
 	}