Reduce the amount of code duplication by always passing
the TCGMemOpIdx argument to helper_atomic_*. This is not
currently used for user-only, but it's easy to ignore.
Tested-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>