dts: arm: adi: Update MAX32657 low power states and residencies

Set MAX32657 cpu power states as idle, standby and powerdown. Power down
mode is disabled by default and can only be entered by calling
pm_state_force. Note that residency durations may need to be updated
depending on the resolution of chosen sleep timer.

Signed-off-by: Tahsin Mutlugun <Tahsin.Mutlugun@analog.com>