usb:udc: Remove duplicated USB definitions from include/linux/usb/ch9.h file

Remove the repeated USB descriptor code and use usbdescriptors.h file.
ch9.h file has been copied from linux and is needed for USB gadget
related work.
Now usbdescriptors.h and ch9.h shall be used together.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Vasut <marex@denx.de>
diff --git a/drivers/usb/gadget/usbstring.c b/drivers/usb/gadget/usbstring.c
index 95555cf..4dbe060 100644
--- a/drivers/usb/gadget/usbstring.c
+++ b/drivers/usb/gadget/usbstring.c
@@ -13,6 +13,7 @@
 #include <common.h>
 #include <asm/errno.h>
 #include <linux/usb/ch9.h>
+#include <usbdescriptors.h>
 #include <linux/usb/gadget.h>
 
 #include <asm/unaligned.h>