arm64: dts: qcom: pm660l: Support SPMI regulators on PMIC sid 3

The PM660L PMIC has SPMI regulators on the PMIC SID 3: let's add
the compatible in order to probe them.

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/20210728222542.54269-23-konrad.dybcio@somainline.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>