intel/compiler: Drop unused saturate handling in repclear shader

We never set key->clamp_fragment_color when compiling the BLORP fast
clear shaders.  Besides, we were setting saturate on an FB write opcode,
which...isn't even a thing.  We would need it on the MOV, and weren't
setting it there.  So it wouldn't have even worked.

Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20172>

src/intel/compiler/brw_fs.cpp

@@ -3625,7 +3625,6 @@ fs_visitor::emit_repclear_shader()
          bld.exec_all().group(1, 0).MOV(component(header, 2), brw_imm_ud(i));
 
       write = bld.emit(FS_OPCODE_REP_FB_WRITE);
-      write->saturate = key->clamp_fragment_color;
       write->target = i;
       /* We can use a headerless message for the first render target */
       write->header_size = i == 0 ? 0 : 2;