mfd: max8997: Enale irq-wakeup unconditionally

mfd: max8997: Enale irq-wakeup unconditionally

IRQ wake up support for MAX8997 driver was initially configured by
respective property in pdata. However, after the driver conversion to
device-tree, setting it was left as 'todo'. Nowadays most of other PMIC MFD
drivers initialized from device-tree assume that they can be an irq wakeup
source, so enable it also for MAX8997. This fixes support for wakeup from
MAX8997 RTC alarm.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>