USB: usbcore get rid of the timer in usb_start_wait_urb()

This patch uses completion timeout instead of a timer to implement
a timeout when submitting an URB in usb_start_wait_urb().

It also fixes a small issue. With the previous code, if no timeout
happened and the URB's status was set to ECONNRESET value, the code
assumed wrongly that a timeout had occured.

Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>