dt-bindings: crypto: fsl-dcp: add imx6sl and imx6ull compatible

Currently the dtbs_check for imx6 generates warnings like this:

'fsl,imx6sl-dcp' is not one of ['fsl,imx23-dcp', 'fsl,imx28-dcp']
['fsl,imx6sl-dcp', 'fsl,imx28-dcp'] is too long

or

'fsl,imx6ull-dcp' is not one of ['fsl,imx23-dcp', 'fsl,imx28-dcp']
['fsl,imx6ull-dcp', 'fsl,imx28-dcp'] is too long

So add them to the devicetree binding.
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230530100843.15072-2-stefan.wahren@i2se.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/crypto/fsl-dcp.yaml

@@ -11,9 +11,15 @@ maintainers:
 
 properties:
   compatible:
-    enum:
-      - fsl,imx23-dcp
-      - fsl,imx28-dcp
+    oneOf:
+      - enum:
+          - fsl,imx23-dcp
+          - fsl,imx28-dcp
+      - items:
+          - enum:
+              - fsl,imx6sl-dcp
+              - fsl,imx6ull-dcp
+          - const: fsl,imx28-dcp
 
   reg:
     maxItems: 1