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/configs/galileo_defconfig b/configs/galileo_defconfig
index f208651..9b0f969 100644
--- a/configs/galileo_defconfig
+++ b/configs/galileo_defconfig
@@ -4,3 +4,6 @@
 CONFIG_OF_CONTROL=y
 CONFIG_OF_SEPARATE=y
 CONFIG_DEFAULT_DEVICE_TREE="galileo"
+CONFIG_ETH_DESIGNWARE=y
+CONFIG_NETDEVICES=y
+CONFIG_NET=y