The actual offset of the start of VBI data is incorrectly documented for both
the cx2388x and bt8x8.  For the cx2388x, it appears to be about 220 to 224 +
VBI_V_DEL*2.  The driver has been incorrectly reporting an offset of 244.
This patch adjusts VBI_V_DEL to 10, so that the offset of 244 is correct.
This is the same offset as the bttv driver, and expected by some software.
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>