Input: xpad - ensure xpad->bulk_out is initialized before submitting urb

As pointed out by Oliver Neukum:
xpad->irq_in is currently submitted before xpad->bulk_out is allocated.
That however is a race, because the callback for irq_in can call
xpad360w_process_packet(), which will in turn submit the bulk URB.

This patch moves initialization for xpad->bulk_out earlier, so we can
ensure xpad->bulk_out is initialized before submitting urb.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>