LoongArch: dts: Add SDIO controller support to Loongson-2K0500

The Loongson-2K0500 integrates two SDIO controllers for SD storage cards
and SDIO cards, supporting SD storage card boot.

The module is supported now, enable it.

Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>