USB: gadget.h depends on ch9.h so include ch9.h directly

The struct definitions are used.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index dd1571d..55d1a88 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -16,6 +16,7 @@
 #define __LINUX_USB_GADGET_H
 
 #include <linux/slab.h>
+#include <linux/usb/ch9.h>
 
 struct usb_ep;