drm/i915/tc: Make the TC mode readout consistent in all PHY states

For consistency detect the initial TC mode in the PHY owned state the
same way this is done in the not owned state (w/o changing the
behavior). While at it, add more details to the PHY state debug print.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230316131724.359612-11-imre.deak@intel.com