migration: HMP: Fix postcopy latency distribution label

Fix the loop condition to avoid having a label with "1000 us" instead
of "1 ms".

Reported-by: Prasad Pandit <ppandit@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/qemu-devel/20250716182648.30202-3-farosas@suse.de
Signed-off-by: Fabiano Rosas <farosas@suse.de>
1 file changed