soc: openisa_rv32m1: Implement sys_arch_reboot()
soc: openisa_rv32m1: Implement sys_arch_reboot()

Implements sys_arch_reboot() on the openisa_rv32m1 soc to enable zephyr
micropython on the rv32m1_vega board.

Signed-off-by: Maureen Helm <87a696db5547fa477bda9f9e0f00013c839c14d3@nxp.com>

galak/zephyr,finikorg/zephyr,ldts/zephyr,ldts/zephyr,finikorg/zephyr,finikorg/zephyr,nashif/zephyr,nashif/zephyr,ldts/zephyr,Vudentz/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,ldts/zephyr,Vudentz/zephyr,galak/zephyr,Vudentz/zephyr,nashif/zephyr,nashif/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr