dt-bindings: mmc: hisilicon,hi3660-dw-mshc: Convert to DT schema

dt-bindings: mmc: hisilicon,hi3660-dw-mshc: Convert to DT schema

Convert the Hisilicon DesignWare Mobile Storage Host Controller
(dw-mshc) bindings from text format to DT schema.

As part of this conversion, the binding file is renamed from
k3-dw-mshc.txt to hisilicon,hi3660-dw-mshc.yaml to align with compatible
string naming conventions. Examples have been updated to pass schema
validation.

Note: synopsys-dw-mshc binding specifies clock names as "biu" followed
by "ciu". However, this Hisilicon binding reverses the order to 'ciu'
then 'biu' to match both the legacy text binding and in-kernel Hisilicon
DTS board files.

Signed-off-by: Bhargav Joshi <rougueprince47@gmail.com>
Acked-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>