alpha: use set_irq_chip and push down __do_IRQ to the machine types

Also kill superfluous IRQ_DISABLED initialization, since that's the
default state of the irq_desc[i].status field.

Tested-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Kyle McMartin <kyle@redhat.com>
Signed-off-by: Matt Turner <mattst88@gmail.com>
diff --git a/arch/alpha/kernel/sys_jensen.c b/arch/alpha/kernel/sys_jensen.c
index 7a7ae36..5b64f91 100644
--- a/arch/alpha/kernel/sys_jensen.c
+++ b/arch/alpha/kernel/sys_jensen.c
@@ -206,11 +206,11 @@
 {
 	init_i8259a_irqs();
 
-	irq_desc[1].chip = &jensen_local_irq_type;
-	irq_desc[4].chip = &jensen_local_irq_type;
-	irq_desc[3].chip = &jensen_local_irq_type;
-	irq_desc[7].chip = &jensen_local_irq_type;
-	irq_desc[9].chip = &jensen_local_irq_type;
+	set_irq_chip_and_handler(1, &jensen_local_irq_type, alpha_do_IRQ);
+	set_irq_chip_and_handler(4, &jensen_local_irq_type, alpha_do_IRQ);
+	set_irq_chip_and_handler(3, &jensen_local_irq_type, alpha_do_IRQ);
+	set_irq_chip_and_handler(7, &jensen_local_irq_type, alpha_do_IRQ);
+	set_irq_chip_and_handler(9, &jensen_local_irq_type, alpha_do_IRQ);
 
 	common_init_isa_dma();
 }