floppy: call disk_force_media_change when changing the format

While changing the format of a floppy isn't strictly speaking a media
change, the effects are the same in that the content of the media
changes and the diskseq should be increased and uevent should be
sent.  Switch from calling __invalidate_device to
disk_force_media_change to do so.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Message-Id: <20230811100828.1897174-10-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>