loader: cleanup copyright section
loader: cleanup copyright section

With previous patches nearly all the original code (as seen in the
various loaders) is gone.

Update the copyright/license section to reflect that.

Signed-off-by: Emil Velikov <f20878473f414da183da19ee25c8722cc1d711e4@collabora.com>
Reviewed-by: Axel Davy <2b6ef604b998fb81662f85c329e4fc020eae8e5d@ens.fr>
Reviewed-by: Nicolai Hähnle <0d0be6cf5ad662651be2dc5dfd44aa2b09d4c1cc@amd.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler