kconfig: add blank Kconfig files

This would be useful to start moving various config options.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
diff --git a/net/Kconfig b/net/Kconfig
new file mode 100644
index 0000000..22b9eaa
--- /dev/null
+++ b/net/Kconfig
@@ -0,0 +1,10 @@
+#
+# Network configuration
+#
+
+menuconfig NET
+	bool "Networking support"
+
+if NET
+
+endif   # if NET