intel/vec4: Don't try both sources as immediates for DPH

DPH isn't actually commutative, so this doesn't work.  If the immediate
in src0 would be a VF candidate, we could do better. *shrug*

No shader-db changes on any Intel platform.

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Fixes: b04beaf41d ("intel/vec4: Try both sources as candidates for being immediates")

src/intel/compiler/brw_vec4_nir.cpp

@@ -1951,7 +1951,7 @@ vec4_visitor::nir_emit_alu(nir_alu_instr *instr)
       break;
 
    case nir_op_fdph_replicated:
-      try_immediate_source(instr, op, true, devinfo);
+      try_immediate_source(instr, op, false, devinfo);
       inst = emit(BRW_OPCODE_DPH, dst, op[0], op[1]);
       inst->saturate = instr->dest.saturate;
       break;