block/blk-iocost: Combine two error paths in ioc_qos_write()

block/blk-iocost: Combine two error paths in ioc_qos_write()

Reduce code duplication by combining two error paths. No functionality
has been changed.

Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://patch.msgid.link/80d4fc1ecd5eaf187c0a31c63a1033a7326d4c7e.1780682325.git.bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>