arm64: dts: qcom: sm8450: align MMC node names with dtschema

The bindings expect "mmc" for MMC/SDHCI nodes:

  qcom/sm8450-sony-xperia-nagara-pdx223.dtb: sdhci@8804000: $nodename:0: 'sdhci@8804000' does not match '^mmc(@.*)?$'

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221204094438.73288-1-krzysztof.kozlowski@linaro.org