usb: gadget: hid: add configfs support

Make the hid function available for gadgets composed with configfs.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index ea2d770..747ef53 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -413,6 +413,16 @@
 	  connections can then be made on the gadget system, using
 	  ALSA's aconnect utility etc.
 
+config USB_CONFIGFS_F_HID
+	boolean "HID function"
+	depends on USB_CONFIGFS
+	select USB_F_HID
+	help
+	  The HID function driver provides generic emulation of USB
+	  Human Interface Devices (HID).
+
+	  For more information, see Documentation/usb/gadget_hid.txt.
+
 source "drivers/usb/gadget/legacy/Kconfig"
 
 endchoice