drm/i915: VBT Parser cleanup for eDP block

Support for parsing parameters for S3D support and T3 optimization
support is implemented. The order for the bdb_edp struct was also
made similar to that indicated in spec.

Signed-off-by: Rohit Jain <rohit.jain@intel.com>
Reviewed-by: Shobhit Kumar <shobhit.kumar@intel.com>
Reviewed-by: Vijay A. Purushothaman <vijay.a.purushothaman@intel.com>
Reviewed-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Acked-by: Jesse Barnes <jesse.barnes@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>