drm/i915/dpio: Add per-lane PHY TX register definitons for bxt/glk

drm/i915/dpio: Add per-lane PHY TX register definitons for bxt/glk

Add consistent definitions for the per-lane PHY TX registers
on bxt/glk. The current situation is a slight mess with some
registers having a LN0 define, while others have a parametrized
per-lane definition.

v2: Adjust gvt accordingly

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240417151211.32135-1-ville.syrjala@linux.intel.com