intel/fs: Only use SLM fence in compute shaders

Fixes: b390ff3517 ("intel/fs: Add support for SLM fence in Gen11")
Fixes: e142061399 ("intel/fs: Implement scoped_memory_barrier")

Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>

src/intel/compiler/brw_fs_nir.cpp

@@ -4299,6 +4299,9 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr
          }
       }
 
+      if (stage != MESA_SHADER_COMPUTE)
+         slm_fence = false;
+
       /* Be conservative in Gen11+ and always stall in a fence.  Since there
        * are two different fences, and shader might want to synchronize
        * between them.