* Realtek rts39xx SoC SDIO host controller

Required properties/subnode:
- compatible: Should be "realtek,rts-sdhc"
- reg: Address and length of the register set for the device
- interrupt-parent: Phandle of the parent interrupt controller
- interrupts: Should contain sdio controller interrupt
- resets: List of phandle and reset specifier pairs, one pair for
each reset signal that affects the device.
- reset-names: List of reset signal name strings sorted in the same order as
the resets property.
- disable-wp: make card always writable.
- cd-inverted: when present, polarity on the CD line is inverted.
- sd-pwr-en-inverted: when present, the logical of SD_PWR_EN is inverted.
- bus-width: Number of data lines, can be <1>, <4>, or <8>.  The default
  will be <1> if the property is absent.
- cap-sd-highspeed: SD high-speed timing is supported
- cap-mmc-highspeed: MMC high-speed timing is supported
- sd-uhs-sdr12: SD UHS SDR12 speed is supported
- sd-uhs-sdr25: SD UHS SDR25 speed is supported
- sd-uhs-sdr50: SD UHS SDR50 speed is supported
- power-ctrl-gpio: sd power ctrl pin number
- votage-switch-ctrl-gpio: sd votage switch ctrl pin number
- pull-ctrl-gpio: sd pull ctrl pin number

Example:
	sdhc: sdhc@18300000 {
		compatible = "realtek,rts-sdhc";
		reg = <0x18300000 0x100000>;
		interrupt-parent = <&vecintc>;
		interrupts = <BSP_IRQ_SD>;
		resets = <&reset FORCE_RESET_SD>,    \
			<&sysmem SYS_MEM_SD_SDIO>;
		reset-names = "reset-sd-device", "sdio-sysmem-up";
		disable-wp;
		cd-inverted;
		bus-width = <8>;
		cap-sd-highspeed;
		cap-mmc-highspeed;
		sd-uhs-sdr12;
		sd-uhs-sdr25;
		sd-uhs-sdr50;
		pwr-ctrl-gpio = <&pinctrl 0 GPIO_ACTIVE_HIGH>;
		votage-switch-ctrl-gpio = <&pinctrl 1 GPIO_ACTIVE_HIGH>;
		pull-ctrl-gpio = <&pinctrl 2 GPIO_ACTIVE_HIGH>;
	};
