dts: riscv: andes: andes_v5_ae350: added CPU number to 8 hart
dts: riscv: andes: andes_v5_ae350: added CPU number to 8 hart

Add cpu node for supporting 8 cores.

Signed-off-by: Kevin Wang <322702d4d85e6886f0b9a283859a700408c5b273@andestech.com>

zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr