floppy: remove redundant assignment to variable st

The variable st is being assigned a value that is never read and
it is being updated later with a new value. The initialization is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Denis Efremov <efremov@linux.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20210415130020.1959951-1-colin.king@canonical.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>