block: fix typos in comments and strings in blk-core

block: fix typos in comments and strings in blk-core

This patch fixes multiple spelling mistakes in comments and documentation
in the file block/blk-core.c.

No functional changes intended.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: shechenglong <shechenglong@xfusion.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>