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/ti/beagle_x15/board.c b/board/ti/beagle_x15/board.c
index ac0d22c..ffcd531 100644
--- a/board/ti/beagle_x15/board.c
+++ b/board/ti/beagle_x15/board.c
@@ -356,7 +356,7 @@
 	if (!getenv("ethaddr")) {
 		printf("<ethaddr> not set. Validating first E-fuse MAC\n");
 
-		if (is_valid_ether_addr(mac_addr))
+		if (is_valid_ethaddr(mac_addr))
 			eth_setenv_enetaddr("ethaddr", mac_addr);
 	}
 
@@ -370,7 +370,7 @@
 	mac_addr[5] = mac_lo & 0xFF;
 
 	if (!getenv("eth1addr")) {
-		if (is_valid_ether_addr(mac_addr))
+		if (is_valid_ethaddr(mac_addr))
 			eth_setenv_enetaddr("eth1addr", mac_addr);
 	}