Deprecates use of filter mode for mipmap filters.

Change-Id: I77044ee7f0ce1b066dd8c8a1ee1b34e07f5e9766
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/128660
Commit-Queue: Loko Kung <lokokung@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>

generator/templates/api_cpp.h

@@ -49,12 +49,6 @@ namespace {{metadata.namespace}} {
 
     {% endfor %}
 
-    // Special case definition of MipmapFilterMode for Dawn side.
-    // TODO(lokokung) Remove once Chromium side is updated.
-    {% if 'dawn' in enabled_tags %}
-         using MipmapFilterMode = FilterMode;
-    {% endif %}
-
     {% for type in by_category["bitmask"] %}
         enum class {{as_cppType(type.name)}} : uint32_t {
             {% for value in type.values %}