dt-bindings: mmc: sdhci-msm: Add compatible string for sc7180

Add sc7180 SoC specific compatible strings for qcom-sdhci controller.

Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/0101016eacb255af-3985262d-9b7e-4813-88c2-61838406e12c-000000@us-west-2.amazonses.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>