dt-bindings: timer: add imx7d compatible

Currently the dtbs_check for imx6ul generates warnings like this:

['fsl,imx7d-gpt', 'fsl,imx6sx-gpt'] is too long

The driver has no special handling for fsl,imx7d-gpt, so fsl,imx6sx-gpt is
used. Therefore make imx7d GPT compatible to the imx6sx one to fix the
warning.

Signed-off-by: Alexander Stein <[email protected]>
Acked-by: Conor Dooley <[email protected]>
Reviewed-by: Rob Herring <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: tq-steina

Documentation/devicetree/bindings/timer/fsl,imxgpt.yaml

@@ -36,7 +36,9 @@ properties:
               - fsl,imxrt1170-gpt
           - const: fsl,imx6dl-gpt
       - items:
-          - const: fsl,imx6ul-gpt
+          - enum:
+              - fsl,imx6ul-gpt
+              - fsl,imx7d-gpt
           - const: fsl,imx6sx-gpt
 
   reg: