max8998 RTC/interrupt issues

[xc-racer99]

There are multiple issues:

1. The GPH0(7) pin needs to be set to PULL_NONE in order for the interrupt to trigger
2. The wakeup-source property should be added to the DTS and parsed in drivers/mfd/max8998 (xc-racer99@80eb214)
3. RTC should be conditionally set to enable wakeup (xc-racer99@6bece19)

[xc-racer99]

Branch created at https://github.com/PabloPL/linux/tree/for-upstream/max8998-interrupt-fixes

@PabloPL if you could test (with using hwclock program in Linux) and submit upstream if it works for you that would be great.

[xc-racer99]

Alright, IRQ fix is now pending upstream (in krzk's for-next branch). RTC patches/wakeup-source haven't been submitted anywhere.