[media] cx231xx: Fix vblank/vactive line counts for PAL/SECAM

Adjust the vblank and vactive counts so that they don't throw an error in
cx25840's set_std call (we did an equivalent change for NTSC when we got the
scaler working).

Signed-off-by: Devin Heitmueller <dheitmueller@hauppauge.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>