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/doc/README.enetaddr b/doc/README.enetaddr
index 1eaeaf9..0fafd2c 100644
--- a/doc/README.enetaddr
+++ b/doc/README.enetaddr
@@ -87,7 +87,7 @@
 Look up an environment variable and convert the stored address.  If the address
 is valid, then the function returns 1.  Otherwise, the function returns 0.  In
 all cases, the enetaddr memory is initialized.  If the env var is not found,
-then it is set to all zeros.  The common function is_valid_ether_addr() is used
+then it is set to all zeros.  The common function is_valid_ethaddr() is used
 to determine address validity.
 uchar enetaddr[6];
 if (!eth_getenv_enetaddr("ethaddr", enetaddr)) {