USB: UAS: use macro for reporting results

The SCSI layer has introduced a new macro for recording the result
of a command. Use it.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20200916094026.30085-3-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>