The Armada 7K/8K use the same RTC IP than the Armada 38x. However the SOC
integration differs in 2 points:
- MBUS bridge timing initialization
- IRQ configuration at SoC level
Moreover the Armada 7K/8K have an issue preventing to get the interrupt
from alarm 1. This commit allows to use alarm 2 for these A7K/8K but to
still use alarm 1 for the Armada 38x.