i965/fs: Fix saturate on MAD and LRP with the NIR backend.
i965/fs: Fix saturate on MAD and LRP with the NIR backend.

Fixes misrendering in "Witcher 2" with INTEL_USE_NIR=1, and probably
many other programs.

Signed-off-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>
Reviewed-by: Jason Ekstrand <b186559eaedf698788888c8a2559b4efb4db10d6@intel.com>
Reviewed-by: Matt Turner <789b315743a28dd066a4ba1459c35951c291d8a6@gmail.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler