kconfig: Add API kconfig file

Add kconfig file to enable API support

Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/Kconfig b/Kconfig
index 0dd21df..81b4226 100644
--- a/Kconfig
+++ b/Kconfig
@@ -308,6 +308,8 @@
 
 endmenu		# Boot images
 
+source "api/Kconfig"
+
 source "common/Kconfig"
 
 source "cmd/Kconfig"
diff --git a/api/Kconfig b/api/Kconfig
new file mode 100644
index 0000000..16731d3
--- /dev/null
+++ b/api/Kconfig
@@ -0,0 +1,9 @@
+menu "API"
+
+config API
+	bool "Enable U-Boot API"
+	default n
+	help
+	  This option enables the U-Boot API. See api/README for more information.
+
+endmenu