USB: avoid urb->pipe in usbfs

This patch (as948) removes most of the references to urb->pipe from
the usbfs routines in devio.c.  The one tricky aspect is in
snoop_urb(), which can be called before the URB is submitted and which
uses usb_urb_dir_in().  For this to work properly, the URB's direction
flag must be set manually in proc_do_submiturb().

The patch also fixes a minor bug; the wValue, wIndex, and wLength
fields were snooped in proc_do_submiturb() without conversion from
le16 to CPU-byte-ordering.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>