migration: Drop cached migration state in migration_maybe_pause()

migration: Drop cached migration state in migration_maybe_pause()

I can't see why we must cache the state now after we avoided possible
CANCEL race: that's the only thing I can think of that can modify the
migration state concurrently with the migration thread itself.  Make all
the state updates to happen always, then we don't need to cache the state
anymore.

Signed-off-by: Peter Xu <peterx@redhat.com>
Tested-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Juraj Marcin <jmarcin@redhat.com>
Link: https://lore.kernel.org/r/20250114230746.3268797-10-peterx@redhat.com
Signed-off-by: Fabiano Rosas <farosas@suse.de>