media: si2168: fix a comment about firmware version

There's a comment there at s82168 that it is wrong.

With firmware 4.0.11, sleep/resume works well without
need of download it every time. But firmware 4.0.19
needs to be downloaded again after sleep.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>