drm/i915: Unify the TypeC port notation in debug/error messages

Unify the TypeC port notation in log messages, so that it matches the
spec. For instance the first ICL TypeC port will read as 'Port C/TC#1'.

v2:
- Format print the name only once. (José)

Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190628143635.22066-9-imre.deak@intel.com