dt-bindings: qcom,pdc: Add compatible for sc7280

Add the compatible string for sc7280 SoC from Qualcomm
Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1615787946-26474-1-git-send-email-rnayak@codeaurora.org

Documentation/devicetree/bindings/interrupt-controller/qcom,pdc.txt

@@ -19,6 +19,7 @@ Properties:
 	Value type: <string>
 	Definition: Should contain "qcom,<soc>-pdc" and "qcom,pdc"
 		    - "qcom,sc7180-pdc": For SC7180
+		    - "qcom,sc7280-pdc": For SC7280
 		    - "qcom,sdm845-pdc": For SDM845
 		    - "qcom,sdm8250-pdc": For SM8250
 		    - "qcom,sdm8350-pdc": For SM8350