drm/i915/bios: Define "TV" child device handle

drm/i915/bios: Define "TV" child device handle

Child device 0x2 used to be "TV" until redefined to mean
EFP5 in version 215. Add a define for the old meaning as well.

Technically it was probably deprecated a lot before version
215 since native TV encoders were last seen on CTG, and SDVO
was fully gone by HSW. So something like "???-164" might also
be a reasonable way to document this, but no real harm in
saying "???-214" since nothing else presumably occupied that
bit in the meantime.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240503122449.27266-7-ville.syrjala@linux.intel.com
Acked-by: Jani Nikula <jani.nikula@intel.com>