[SCSI] advansys: Stop checking the scsi_cmnd belongs to our Scsi_Host

The interrupt routines used to walk the list of Scsi_Hosts belonging to
this driver to make sure that the scsi_cmnd belonged to one of them.
This is a waste of time and gets in the way of later cleanups, so
delete it.

Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>