arm64: dts: qcom: msm8998: add MSM8998 SDCC specific compatible

Add a MSM8998-specific SDCC compatible, because using only a generic
qcom,sdhci-msm-v4 fallback is deprecated.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220714091042.22287-3-krzysztof.kozlowski@linaro.org