i965/miptree: Delete an unused function

We're going to combine ::mcs_buf and ::hiz_buf in later commits. Once
that happens, this function no longer make sense.

Reviewed-by: Rafael Antognolli <rafael.antognolli@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/mesa/drivers/dri/i965/intel_mipmap_tree.c

@@ -3792,19 +3792,6 @@ get_isl_dim_layout(const struct gen_device_info *devinfo,
    unreachable("Invalid texture target");
 }
 
-enum isl_aux_usage
-intel_miptree_get_aux_isl_usage(const struct brw_context *brw,
-                                const struct intel_mipmap_tree *mt)
-{
-   if (mt->hiz_buf)
-      return ISL_AUX_USAGE_HIZ;
-
-   if (!mt->mcs_buf)
-      return ISL_AUX_USAGE_NONE;
-
-   return mt->aux_usage;
-}
-
 bool
 intel_miptree_set_clear_color(struct brw_context *brw,
                               struct intel_mipmap_tree *mt,

src/mesa/drivers/dri/i965/intel_mipmap_tree.h

@@ -485,10 +485,6 @@ enum isl_dim_layout
 get_isl_dim_layout(const struct gen_device_info *devinfo,
                    enum isl_tiling tiling, GLenum target);
 
-enum isl_aux_usage
-intel_miptree_get_aux_isl_usage(const struct brw_context *brw,
-                                const struct intel_mipmap_tree *mt);
-
 void
 intel_get_image_dims(struct gl_texture_image *image,
                      int *width, int *height, int *depth);