mesa/main: Ignore filter state for MS texture completeness
After the discussion in https://github.com/KhronosGroup/OpenGL-API/issues/45 the section 8.17 (texture completeness) of the OpenGL 4.6 core profile was changed to explicitly say that multisample texture completeness ignores filter state of the texture.
"Using the preceding definitions, a texture is complete unless any of the following conditions hold true: ... - The minification filter requires a mipmap (is neither NEAREST nor LINEAR), the texture is not multisample, and the texture is not mipmap complete. - The texture is not multisample; either the magnification filter is not NEAREST, or the minification filter is neither NEAREST nor NEAREST_- MIPMAP_NEAREST; and any of – The internal format of the texture is integer (see table 8.12). – The internal format is STENCIL_INDEX. – The internal format is DEPTH_STENCIL, and the value of DEPTH_- STENCIL_TEXTURE_MODE for the texture is STENCIL_INDEX."