soc: qcom: smd-rpm: Add sdm660 compatible

Add the compatible for the RPM in SDM660, so that rpm resources can be
made available.

Signed-off-by: Craig Tatlor <[e-mail]>
Signed-off-by: Bjorn Andersson <[e-mail]>
Signed-off-by: Andy Gross <[e-mail]>

Documentation/devicetree/bindings/soc/qcom/qcom,smd-rpm.txt

···
 		    "qcom,rpm-msm8916"
 		    "qcom,rpm-msm8974"
 		    "qcom,rpm-msm8998"
+		    "qcom,rpm-sdm660"
 		    "qcom,rpm-qcs404"
 
 - qcom,smd-channels:

drivers/soc/qcom/smd-rpm.c

···
 	{ .compatible = "qcom,rpm-msm8974" },
 	{ .compatible = "qcom,rpm-msm8996" },
 	{ .compatible = "qcom,rpm-msm8998" },
+	{ .compatible = "qcom,rpm-sdm660" },
 	{ .compatible = "qcom,rpm-qcs404" },
 	{}
 };