mfd: tps65218: Fix reported randconfig error
Reported error was:
ERROR: "regmap_del_irq_chip" [drivers/mfd/tps65218.ko] undefined!
when CONFIG_REGMAP_IRQ is not enabled.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>