mesa/pack: use autogenerated format_pack functions
mesa/pack: use autogenerated format_pack functions

Take advantage of new mesa formats and new format_pack functions to
reduce source code in _mesa_pack_rgba_span_from_ints() and
_mesa_pack_rgba_span_from_uints().

Signed-off-by: Samuel Iglesias Gonsalvez <b753b212f30aed827c3eea2e437609dc37310153@igalia.com>
Reviewed-by: Jason Ekstrand <b186559eaedf698788888c8a2559b4efb4db10d6@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler