scsi: stop decoding if scsi_normalize_sense() fails

If scsi_normalize_sense() fails we couldn't decode the sense
buffer, and the scsi_sense_hdr fields are invalid.
For those cases we should rather dump the sense buffer
and not try to decode invalid fields.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>