Pullup or latch DCDC enable lines to allow payload to stay on in case of MMC reset
According to the PICMG spec, when the MMC reboots is firmware, the payload must not be affected.
This can be solved either by adding pullup resistors, or by connecting
enable lines through transparent latch.
Second option seems more robust in case of standalone operation.
See https://github.com/lnls-dig/afc-hw/project/ohr-support/issues/228