[SCSI] sym53c8xx: Stop overriding scsi_done

Instead of telling the reset routine that the command completed from
sym_eh_done, do it from sym_xpt_done.  The 'to_do' element of the ucmd
is redundant -- it serves only to tell whether eh_done is valid or not,
and we can tell this by checking to see if it's NULL.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>