docs: media: fix typo in docs

This patch resolves a spelling error in the documentation.

It is submitted as part of my application to the "Linux Kernel Bug
Fixing Spring Unpaid 2024" mentorship program of the Linux Kernel
Foundation.

Signed-off-by: Vincenzo Mezzela <vincenzo.mezzela@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>