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: Will McVicker <willmcvicker@google.com>
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/20201127140559.381351-4-gregkh@linuxfoundation.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>