PM: hibernate: Convert to bdev_open_by_dev()

Convert hibernation code to use bdev_open_by_dev().

CC: linux-pm@vger.kernel.org
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-16-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>