arm64: dts: qcom: sdm630: Add SDHCI2 node

This will enable usage of (generally) uSD cards.
While at it, add accompanying OPP table for DVFS.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Link: https://lore.kernel.org/r/20210728222542.54269-10-konrad.dybcio@somainline.org


[bjorn: Dropped "sdhci1-" prefix from opp-table node]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>