lib: utils/reset: Add Andes fdt reset driver support

Add ATCWDT200 as reset device of AE350 platform, this driver requires
SMU to program the reset vector registers before triggering WDT software
restart signal.

dts example:

  smu@f0100000 {
    compatible = "andestech,atcsmu";
    reg = <0x00000000 0xf0100000 0x00000000 0x00001000>;
  };

  wdt: wdt@f0500000 {
    compatible = "andestech,atcwdt200";
    reg = <0x00000000 0xf0500000 0x00000000 0x00001000>;
    interrupts = <3 4>;
    interrupt-parent = <&plic0>;
    clock-frequency = <15000000>;
  };

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>