dt-bindings: vendor-prefixes: Add an entry for Protonic Holland

Add "prt" entry for Protonic Holland: https://www.protonic.nl/en/

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index d389138..325e537 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -808,6 +808,8 @@
     description: Primux Trading, S.L.
   "^probox2,.*":
     description: PROBOX2 (by W2COMP Co., Ltd.)
+  "^prt,.*":
+    description: Protonic Holland
   "^pulsedlight,.*":
     description: PulsedLight, Inc
   "^purism,.*":