st/mesa: enable ARB_shader_viewport_layer_array
st/mesa: enable ARB_shader_viewport_layer_array

Reviewed-by: Marek Olšák <8c7344a1abdb103e79ecfd488098373070c3c70e@amd.com>
Reviewed-by: Edward O'Callaghan <b035da0d7e151e09fe2005f3a7bc526beb9b3245@folklore1984.net>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler