amiflop: don't call fsync_bdev in FDFMTBEG

FDFMTBEG is used by fdformat to calibrate before formatting a disk.
Neither the atari nor PC floppy driver sync data, which also seems
a bit pointless for a disk hat is about to get formatted.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Message-Id: <20230811100828.1897174-11-hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>