mesa: added GL_DU8DV8_ATI case in _mesa_components_in_format()

This gets hit when glTexSubImage2D() is called with format==GL_DU8DV8_ATI.

src/mesa/main/image.c

@@ -294,6 +294,7 @@ _mesa_components_in_format( GLenum format )
       case GL_DEPTH_STENCIL_EXT:
          return 2;
       case GL_DUDV_ATI:
+      case GL_DU8DV8_ATI:
          return 2;
       default:
          return -1;