um: Remove stale irq_chip.end

irq_chip.end got obsolete with the remnoval of __do_IRQ().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20110206224515.135703209@linutronix.de>

arch/um/kernel/irq.c

@@ -374,7 +374,6 @@ static struct irq_chip normal_irq_type = {
 	.disable = dummy,
 	.enable = dummy,
 	.ack = dummy,
-	.end = dummy
 };
 
 static struct irq_chip SIGVTALRM_irq_type = {
@@ -384,7 +383,6 @@ static struct irq_chip SIGVTALRM_irq_type = {
 	.disable = dummy,
 	.enable = dummy,
 	.ack = dummy,
-	.end = dummy
 };
 
 void __init init_IRQ(void)