dt-bindings: mmc: sdhci-msm: Document the SDX55 compatible

dt-bindings: mmc: sdhci-msm: Document the SDX55 compatible

The SDHCI controller on SDX55 is based on MSM SDHCI v5 IP. Hence,
document the compatible with "qcom,sdhci-msm-v5" as the fallback.
While at it, let's also sort the compatibles in ascending order.

Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-mmc@vger.kernel.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210107143118.2386-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>