net: Remove all references to CONFIG_ETHADDR and friends

We really don't want boards defining fixed MAC addresses in their config
so we just remove the option to set it in a fixed way. If you must have
a MAC address that was not provisioned, then use the random MAC address
functionality.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/README.enetaddr b/doc/README.enetaddr
index 82c9cd5..50e4899 100644
--- a/doc/README.enetaddr
+++ b/doc/README.enetaddr
@@ -15,7 +15,7 @@
  - board-specific location (eeprom, dedicated flash, ...)
 	Note: only used when mandatory due to hardware design etc...
 
- - environment ("ethaddr", "eth1addr", ...) (see CONFIG_ETHADDR)
+ - environment ("ethaddr", "eth1addr", ...)
 	Note: this is the preferred way to permanently store MAC addresses
 
  - ethernet data (struct eth_device -> enetaddr)