bcachefs: Add a missing rhashtable_destroy() call

Fixes https://lore.kernel.org/linux-bcachefs/784c3e6a-75bd-e6ca-535a-43b3e1daf643@kernel.dk/T/#mbf7caf005f960018eba23b58795d06c06c947411Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/movinggc.c

@@ -369,6 +369,7 @@ static int bch2_copygc_thread(void *arg)
 	}
 
 	move_buckets_wait(&trans, &ctxt, &move_buckets, true);
+	rhashtable_destroy(&move_buckets.table);
 	bch2_trans_exit(&trans);
 	bch2_moving_ctxt_exit(&ctxt);