include/exec/memop.h: Expand comment for MO_ATOM_SUBALIGN

Expand the example in the comment documenting MO_ATOM_SUBALIGN,
to be clearer about the atomicity guarantees it represents.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250228103222.1838913-1-peter.maydell@linaro.org
1 file changed