block: fix comment typo in submit_bio of block-core.c.

This patch fix a comment typo in block-core.c.

Signed-off-by: Ping-Xiang Chen <p.x.chen@uci.edu>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220914074237.31621-1-p.x.chen@uci.edu


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