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

arch/arm64/boot/dts/qcom/pm660l.dtsi

@@ -48,6 +48,10 @@ pm660l_wled: leds@d800 {
 
 			status = "disabled";
 		};
+
+		pm660l_spmi_regulators: pm660l-regulators {
+			compatible = "qcom,pm660l-regulators";
+		};
 	};
 };