travis: Add radv vulkan driver to continuous integration
travis: Add radv vulkan driver to continuous integration

Signed-off-by: Rhys Kidd <0b3b315d08353e2046d43a86d41e3fd1dff3d6ad@gmail.com>
Reviewed-by: Andres Gomez <1948e91ee7852f22bc880d172a32ffca98fb60fa@igalia.com>
Reviewed-by: Emil Velikov <f20878473f414da183da19ee25c8722cc1d711e4@collabora.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler