x86: HPET: enter hpet_interrupt_handler with interrupts disabled

Some functions that may be called from this handler require that
interrupts are disabled. Also, combining IRQF_DISABLED and
IRQF_SHARED does not reliably disable interrupts in a handler, so
remove IRQF_SHARED from the irq flags (this irq is not shared anyway).

Signed-off-by: Matt Fleming <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: "Will Newton" <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>

arch/x86/kernel/hpet.c

···
 {
 
 	if (request_irq(dev->irq, hpet_interrupt_handler,
-			IRQF_SHARED|IRQF_NOBALANCING, dev->name, dev))
+			IRQF_DISABLED|IRQF_NOBALANCING, dev->name, dev))
 		return -1;
 
 	disable_irq(dev->irq);