st/mesa: enable ARB_enhanced_layouts on nir drivers

I'm guessing this may have been disable because of missing
component packing support. However recent nir linking changes
required nir based gallium drivers to support component packing
so this should now be ok to enable.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/mesa/state_tracker/st_extensions.c

@@ -956,9 +956,7 @@ void st_init_extensions(struct pipe_screen *screen,
    }
 
    if (consts->GLSLVersion >= 140) {
-      if (screen->get_param(screen, PIPE_CAP_TGSI_ARRAY_COMPONENTS) &&
-         screen->get_shader_param(screen, PIPE_SHADER_FRAGMENT,
-                                   PIPE_SHADER_CAP_PREFERRED_IR) == PIPE_SHADER_IR_TGSI)
+      if (screen->get_param(screen, PIPE_CAP_TGSI_ARRAY_COMPONENTS))
          extensions->ARB_enhanced_layouts = GL_TRUE;
    }