mfd: pm8xxx: revert "disassociate old virq if hwirq mapping already exists"

Now that ssbi-gpio is a proper hierarchical IRQ chip, and all in-tree
users of device tree have been updated, we can now drop the hack that
was introduced to disassociate the old Linux virq if a hwirq mapping
already exists. That patch was introduced to not break git bisect for
any existing boards.

This change was tested on an APQ8060 DragonBoard.
Signed-off-by: Brian Masney <masneyb@onstation.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/mfd/qcom-pm8xxx.c

@@ -380,12 +380,6 @@ static void pm8xxx_irq_domain_map(struct pm_irq_chip *chip,
 				  struct irq_domain *domain, unsigned int irq,
 				  irq_hw_number_t hwirq, unsigned int type)
 {
-	unsigned int old_virq;
-
-	old_virq = irq_find_mapping(domain, hwirq);
-	if (old_virq)
-		irq_domain_disassociate(domain, old_virq);
-
 	irq_domain_set_info(domain, irq, hwirq, chip->pm_irq_data->irq_chip,
 			    chip, handle_level_irq, NULL, NULL);
 	irq_set_noprobe(irq);