platform_get_resource fails when it is a child of a simple-mfd node

[shenki]

This fails to load the timeriomem_rng driver:

                          syscon: syscon@1e6e2000 {
                                  compatible = "aspeed,ast2500-scu", "syscon", "simple-mfd";
                                  reg = <0x1e6e2000 0x1a8>;
                                  #address-cells = <1>;
                                  #size-cells = <0>;
                                  #clock-cells = <1>;
                                  #reset-cells = <1>;
                                  hwrng@78 {
                                          compatible = "timeriomem_rng";
                                          reg = <0x1e6e2078 0x4>;
                                          period = <1>;
                                          quality = <100>;
                                  };
                          };

The line that fails is in drivers/char/hw_random/timeriomem-rng.c timeriomem_rng_probe:

          res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
          if (!res)
                  return -ENXIO;

If I move the hwrng node out of the syscon, it does load.