USB: gadget: f_midi: setup SuperSpeed Plus descriptors

Needed for SuperSpeed Plus support for f_midi.  This allows the
gadget to work properly without crashing at SuperSpeed rates.

Cc: Felipe Balbi <balbi@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NWill McVicker <willmcvicker@google.com>
Reviewed-by: NPeter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/20201127140559.381351-4-gregkh@linuxfoundation.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/f_midi.c

@@ -1048,6 +1048,12 @@ static int f_midi_bind(struct usb_configuration *c, struct usb_function *f)
 		f->ss_descriptors = usb_copy_descriptors(midi_function);
 		if (!f->ss_descriptors)
 			goto fail_f_midi;
+
+		if (gadget_is_superspeed_plus(c->cdev->gadget)) {
+			f->ssp_descriptors = usb_copy_descriptors(midi_function);
+			if (!f->ssp_descriptors)
+				goto fail_f_midi;
+		}
 	}
 
 	kfree(midi_function);