xfs: fix various typos

Signed-off-by: Malcolm Parsons <malcolm.parsons@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index ee1a0c1..a1cc132 100644
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -63,7 +63,7 @@
  */
 
 typedef struct xfs_iomap {
-	xfs_daddr_t		iomap_bn;	/* first 512b blk of mapping */
+	xfs_daddr_t		iomap_bn;	/* first 512B blk of mapping */
 	xfs_buftarg_t		*iomap_target;
 	xfs_off_t		iomap_offset;	/* offset of mapping, bytes */
 	xfs_off_t		iomap_bsize;	/* size of mapping, bytes */