[PATCH] libata: always generate sense if qc->err_mask is non-zero

Current sense generation code does not generate sense error if status
register value doesn't indicate error condition.  However, LLDD's may
indicate errors which 't show up in status register.  Completing such
qc's without generating sense results in successful completion of
failed commands.

Invoke ata_to_sense_error() regardless of status register if
qc->err_mask is not zero such that ata_to_sense_error() generates
default sense error.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>