[PATCH] doc: blkmap: Fix typo in command example

[Quentin Schulz]

Hi Ken,

On 9/26/24 11:26 AM, Ken Kurematsu wrote:
> [You don't often get email from k.kurematsu at nskint.co.jp. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
> 
> Fixed a variable that was incorrect during the calculation of fileblks.
> 
> Signed-off-by: Ken Kurematsu <k.kurematsu at nskint.co.jp>

Reviewed-by: Quentin Schulz <quentin.schulz at cherry.de>

Thanks!
Quentin