advansys: use host_reset

The advansys_reset() function is actually a host reset, not a
bus reset. And there is no need to have a 'last_reset'
value; the same value exists in struct Scsi_Host.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>