dt-bindings: vendor-prefixes: add second Synopsys prefix

There are few bindings with compatibles starting with a "synopsys"
prefix.  Document it as deprecated, to be sure no new usages will
appear.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220221082228.34407-2-krzysztof.kozlowski@canonical.com

Documentation/devicetree/bindings/vendor-prefixes.yaml

@@ -1186,6 +1186,9 @@ patternProperties:
     description: Synaptics Inc.
   "^synology,.*":
     description: Synology, Inc.
+  "^synopsys,.*":
+    description: Synopsys, Inc. (deprecated, use snps)
+    deprecated: true
   "^tbs,.*":
     description: TBS Technologies
   "^tbs-biometrics,.*":