dt-bindings: vendor-prefixes: Document Argon40

Argon 40 Technologies Limited is a SBC expansion board vendor.
Document the prefix. For details see https://argon40.com .

Acked-by: Conor Dooley <[e-mail]>
Signed-off-by: Marek Vasut <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>

Documentation/devicetree/bindings/vendor-prefixes.yaml

···
     description: Arctic Sand
   "^arcx,.*":
     description: arcx Inc. / Archronix Inc.
+  "^argon40,.*":
+    description: Argon 40 Technologies Limited
   "^ariaboard,.*":
     description: Shanghai Novotech Co., Ltd. (Ariaboard)
   "^aries,.*":