[SCSI] set resid in scsi_io_completion() even for check condition

Some targets can return both valid data and sense information.
Always update the request data_len from the SCSI command residual.
Callers should interpret sense data to determine what parts of the
data are valid in case of a CHECK CONDITION status.

Signed-off-by: Pete Wyckoff <pw@osc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>