dt-bindings: Add SpinalHDL vendor

Adds SpinalHDL as vendor. This project provides FPGA IPs including
VexRiscV CPU.
Signed-off-by: Sebastien Van Cauwenberghe <svancau@gmail.com>
Link: https://lore.kernel.org/r/20211011100531.443157-1-svancau@gmail.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.yaml

@@ -1100,6 +1100,8 @@ patternProperties:
     description: Spansion Inc.
   "^sparkfun,.*":
     description: SparkFun Electronics
+  "^spinalhdl,.*":
+    description: SpinalHDL
   "^sprd,.*":
     description: Spreadtrum Communications Inc.
   "^sst,.*":