dts: Add vendor-prefixes.txt file

rlubos · rlubos · commit f775f2430ada · 2021-11-09T12:30:06.000+01:00
"pixart" is not defined in the upstream vendor-prefixes.txt, therefore
add it to a local file.

Signed-off-by: Robert Lubos &lt;robert.lubos@nordicsemi.no&gt;
diff --git a/dts/bindings/vendor-prefixes.txt b/dts/bindings/vendor-prefixes.txt
@@ -0,0 +1 @@
+pixart	PixArt Imaging Inc.
