staging/color-management: credit Niels

Niels' efforts predate Sebastian's by another 5 years and they deserve
to be mentioned.

Sorry for missing them from the commit.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

staging/color-management/README

@@ -3,3 +3,9 @@ Color management and HDR protocol
 Maintainers:
 Sebastian Wick <sebastian at sebastianwick.net>
 Pekka Paalanen <pekka.paalanen@collabora.com>
+
+
+Historical credits not mentioned in the first commit:
+
+- Niels Ole Salscheider, for an early protocol version
+  https://lists.freedesktop.org/archives/wayland-devel/2014-October/017755.html