gallium: use TXP rather than ExtDivide flag

src/mesa/state_tracker/st_mesa_to_tgsi.c

@@ -513,10 +513,9 @@ compile_instruction(
    case OPCODE_TXP:
       /* texture lookup with divide by Q component */
       /* convert to TEX w/ special flag for division */
-      fullinst->Instruction.Opcode = TGSI_OPCODE_TEX;
+      fullinst->Instruction.Opcode = TGSI_OPCODE_TXP;
       fullinst->Instruction.NumSrcRegs = 2;
       fullinst->InstructionExtTexture.Texture = map_texture_target( inst->TexSrcTarget );
-      fullinst->FullSrcRegisters[0].SrcRegisterExtSwz.ExtDivide = TGSI_EXTSWIZZLE_W;
       fullinst->FullSrcRegisters[1].SrcRegister.File = TGSI_FILE_SAMPLER;
       fullinst->FullSrcRegisters[1].SrcRegister.Index = inst->TexSrcUnit;
       break;