scsi: fdomain_isa: use CFG1_IRQ_MASK

Commit 1697c6a6 ("scsi: fdomain: Add register definitions") somehow
missed the uses of CFG1_IRQ_MASK in the Futire Domain ISA driver, leaving
the magic numbers intact.  Fix this issue (with no change in the generated
object file), removing an excess empty line, while at it...

Fixes: 1697c6a6 ("scsi: fdomain: Add register definitions")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>