Remove obsolete header file

usbdescriptors.h conflicts with linux/usb/ch9.h
Remove it.

Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>

drivers/usb/gadget/f_dfu.c

@@ -25,7 +25,6 @@
 #include <malloc.h>
 
 #include <linux/usb/ch9.h>
-#include <usbdescriptors.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb/composite.h>
 

include/g_dnl.h

@@ -22,7 +22,6 @@
 #define __G_DOWNLOAD_H_
 
 #include <linux/usb/ch9.h>
-#include <usbdescriptors.h>
 #include <linux/usb/gadget.h>
 
 int g_dnl_register(const char *s);