arm64: dts: qcom: msm8916: Add "qcom,msm8916-sdhci" compatible

According to Documentation/devicetree/bindings/mmc/sdhci-msm.txt
a SoC specific compatible should be used in addition to the IP version
compatible, but for some reason it was never added for MSM8916.

Add the "qcom,msm8916-sdhci" compatible additionally to make the
device tree match the documented bindings.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210921152120.6710-3-stephan@gerhold.net