dasd: cleamup dasd_state_basic_to_ready

Reflow dasd_state_basic_to_ready a bit to make it easier to modify.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20240228133742.806274-2-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>