dt-bindings: Add vendor prefix for INSIDE Secure

This commits adds a vendor for the company INSIDE Secure.
See https://www.insidesecure.com, for more details.

Signed-off-by: Romain Perier <romain.perier@free-electrons.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -135,6 +135,7 @@ infineon Infineon Technologies
 inforce	Inforce Computing
 ingenic	Ingenic Semiconductor
 innolux	Innolux Corporation
+inside-secure	INSIDE Secure
 intel	Intel Corporation
 intercontrol	Inter Control Group
 invensense	InvenSense Inc.