sil24_error_intr logs all error interrupts.  ATAPI devices generates
many harmless errors which can be ignored and all serious ones are
reported via sense data by SCSI layer.  Don't log device errors from
ATAPI devices.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>