The code was using a homegrown method of looking up the offset
from the irq domain, not to be encouraged. Use the proper
irq_find_mapping() call instead.
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
 {
        struct nmk_gpio_chip *nmk_chip;
        struct irq_chip *host_chip = irq_get_chip(irq);
-       unsigned int first_irq;
 
        chained_irq_enter(host_chip, desc);
 
        nmk_chip = irq_get_handler_data(irq);
-       first_irq = nmk_chip->domain->revmap_data.legacy.first_irq;
        while (status) {
                int bit = __ffs(status);
 
-               generic_handle_irq(first_irq + bit);
+               generic_handle_irq(irq_find_mapping(nmk_chip->domain, bit));
                status &= ~BIT(bit);
        }