glsl: fix xfb_offset unsized array validation

This partially fixes CTS test:
GL44-CTS.enhanced_layouts.xfb_get_program_resource_api

The test now fails at a tes evaluation shader with unsized output arrays.

The ARB_enhanced_layouts spec says:

   "It is a compile-time error to apply xfb_offset to the declaration of an
   unsized array."

So this seems like a bug in the CTS.

Reviewed-by: Dave Airlie <airlied@redhat.com>

src/compiler/glsl/link_varyings.cpp

@@ -40,29 +40,6 @@
 #include "program.h"
 
 
-/**
- * Get the varying type stripped of the outermost array if we're processing
- * a stage whose varyings are arrays indexed by a vertex number (such as
- * geometry shader inputs).
- */
-static const glsl_type *
-get_varying_type(const ir_variable *var, gl_shader_stage stage)
-{
-   const glsl_type *type = var->type;
-
-   if (!var->data.patch &&
-       ((var->data.mode == ir_var_shader_out &&
-         stage == MESA_SHADER_TESS_CTRL) ||
-        (var->data.mode == ir_var_shader_in &&
-         (stage == MESA_SHADER_TESS_CTRL || stage == MESA_SHADER_TESS_EVAL ||
-          stage == MESA_SHADER_GEOMETRY)))) {
-      assert(type->is_array());
-      type = type->fields.array;
-   }
-
-   return type;
-}
-
 static void
 create_xfb_varying_names(void *mem_ctx, const glsl_type *t, char **name,
                          size_t name_length, unsigned *count,