hpet: Switch to irq_get_nr_irqs()

Use the irq_get_nr_irqs() function instead of the global variable
'nr_irqs'. Prepare for changing 'nr_irqs' from an exported global
variable into a variable with file scope.

Signed-off-by: Bart Van Assche <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/all/[email protected]

Author: bvanassche

drivers/char/hpet.c

@@ -162,6 +162,7 @@ static irqreturn_t hpet_interrupt(int irq, void *data)
 
 static void hpet_timer_set_irq(struct hpet_dev *devp)
 {
+	const unsigned int nr_irqs = irq_get_nr_irqs();
 	unsigned long v;
 	int irq, gsi;
 	struct hpet_timer __iomem *timer;