usb: gadget: f_tcm: add configfs support

Allow using the tcm function as a component of a gadget composed with
ConfigFS.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/Documentation/ABI/testing/configfs-usb-gadget-tcm b/Documentation/ABI/testing/configfs-usb-gadget-tcm
new file mode 100644
index 0000000..a29ed2d
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-usb-gadget-tcm
@@ -0,0 +1,6 @@
+What:		/config/usb-gadget/gadget/functions/tcm.name
+Date:		Dec 2015
+KernelVersion:	4.5
+Description:
+		There are no attributes because all the configuration
+		is performed in the "target" subsystem of configfs.