drm/i915: Give DDI encoders even better names

Let's pimp the DDI encoder->name to reflect what the spec calls them.
Ie. on pre-tgl DDI A-F, on tgl+ DDI A-C or DDI TC1-6.

Also since each encoder is really a combination of the DDI and the PHY
we include the PHY name as well.

ICL is a bit special since it already has the two different types
of DDIs (combo or TC) but it still calls them just DDI A-F regarless
of the type. For that let's add an extra "(TC)" note to remind
is which type of DDI it really is.

The code is darn ugly, but not sure there's much we can do about it.

Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201028213323.5423-4-ville.syrjala@linux.intel.com