media: cx231xx: Fix AGC levels for NTSC-M

Windows uses the implemented command sequence to set AGC for NTSC-M.
The previous Linux values work, mostly, but on some embedded
platforms NTSC-M is very unstable. The Windows default values
completely fix any signal stability issues and produce a clear image.

Signed-off-by: Bradford Love <brad@nextdimension.cc>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
This commit is contained in:
Bradford Love 2026-03-12 16:35:25 -05:00 • committed by Hans Verkuil
commit 69426c6c9b