dts: arm: nxp: mcxa: Add power state nodes for mcxa156

1. Add power state nodes for mcxa156, including
sleep, deepsleep and powerdown.

2. Add power management related peripheral nodes
for mcxa156, including spc, cmc, vbat and wuu.

3. Add 'zephyr,cortex-m-idle-timer' node in frdm_mcxa156.

Signed-off-by: Zhaoxiang Jin <Zhaoxiang.Jin_1@nxp.com>