drm/i915: TV modes' parameters sync up with 2D driver

This covers at least:
TV: subcarrier fix for NTSC and PAL
TV: fix timing parameters for PAL, 480p, 1080i

Signed-off-by: Zhenyu Wang <zhenyu.z.wang@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>