block/loop: don't use idr_remove_all()

idr_destroy() can destroy idr by itself and idr_remove_all() is being
deprecated. Drop its usage.

Signed-off-by: Tejun Heo <[e-mail]>
Cc: Jens Axboe <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/block/loop.c

···
 	range = max_loop ? max_loop << part_shift : 1UL << MINORBITS;
 
 	idr_for_each(&loop_index_idr, &loop_exit_cb, NULL);
-	idr_remove_all(&loop_index_idr);
 	idr_destroy(&loop_index_idr);
 
 	blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range);