[hvf] Fix macro usage and metrics calculations. * src/hvf/hvfload.c (hvf_render_callback): Fix glyph loader macro calls and metrics calculations. * src/hvf/hvfobjs.c (hvf_refresh_axis_coordinates, hvf_init_axis_coordinates): Tweak macro usage. * src/hvf/hvfobjs.h (HVF_RenderContext): Remove `face`. * include/freetype/ftmoderr.h: Add HVF error base.