USB: fix usbfs regression

USB: fix usbfs regression

commit 7152b592593b9d48b33f8997b1dfd6df9143f7ec upstream.

This patch (as1352) fixes a bug in the way isochronous input data is
returned to userspace for usbfs transfers.  The entire buffer must be
copied, not just the first actual_length bytes, because the individual
packets will be discontiguous if any of them are short.

Reported-by: Markus Rechberger <mrechberger@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>