Kconfig: Move CONFIG_DESIGNWARE_ETH to Kconfig

Move this to Kconfig and clean up board config files that use it. Also
rename it to CONFIG_ETH_DESIGNWARE to fit with the naming that exists
in drivers/net/Kconfig.

Signed-off-by: Simon Glass <sjg@chromium.org>
Version 1:
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/board/bf609-ezkit/bf609-ezkit.c b/board/bf609-ezkit/bf609-ezkit.c
index 43a4330..86da028 100644
--- a/board/bf609-ezkit/bf609-ezkit.c
+++ b/board/bf609-ezkit/bf609-ezkit.c
@@ -33,7 +33,7 @@
 	return 0;
 }
 
-#ifdef CONFIG_DESIGNWARE_ETH
+#ifdef CONFIG_ETH_DESIGNWARE
 int board_eth_init(bd_t *bis)
 {
 	int ret = 0;