USB: ti_usb_3410_5052: remove unused wait queue

The write wait queue is never added to since commit f1175daa ("USB:
ti_usb_3410_5052: kill custom closing_wait"). Remove it completely.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>