Cut and paste error from the 4-operand memops.

Fixes: ab64da79 ("tcg/tci: Adjust passing of MemOpIdx")
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230608162925.677598-1-richard.henderson@linaro.org>