doc:it_IT: fix file references

Fix italian translation file references based on
`scripts/documentation-file-ref-check` output.

Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>