kbuild: migrate all arch to the kconfig mainmenu upgrade

Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Michal Marek <mmarek@suse.cz>
diff --git a/Kconfig b/Kconfig
new file mode 100644
index 0000000..c13f48d
--- /dev/null
+++ b/Kconfig
@@ -0,0 +1,11 @@
+#
+# For a description of the syntax of this configuration file,
+# see Documentation/kbuild/kconfig-language.txt.
+#
+mainmenu "Linux/$ARCH $KERNELVERSION Kernel Configuration"
+
+config SRCARCH
+	string
+	option env="SRCARCH"
+
+source "arch/$SRCARCH/Kconfig"