r200: Enable GL_EXT_framebuffer_blit

The dd_function_table::BlitFramebuffer is already initialized to
_mesa_meta_BlitFramebuffer, so it should just work.

Tested on a FireGL 8800 (OpenGL renderer string: Mesa DRI R200 (R200
5148) TCL DRI).

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

docs/relnotes/10.1.html

@@ -48,6 +48,7 @@ Note: some of the new features are only available with certain drivers.
 <li>GL_ARB_clear_buffer_object</li>
 <li>GL_ARB_viewport_array on i965.</li>
 <li>GL_AMD_shader_trinary_minmax.</li>
+<li>GL_EXT_framebuffer_blit on r200.</li>
 <li>Reduced memory usage for display lists.</li>
 <li>OpenGL 3.3 support on nv50, nvc0</li>
 </ul>