drm/i915/intel_combo_phy: Print I/O voltage info

Print I/O voltage and process info for each combo phy ports.

v2: Used drm_dbg_kms for logs. (Jani)
Added names for different voltage levels. (Imre)

v3: Used const char * for names. (Jani)

v4: Dropped the procom values and changed commit msg (Imre)

Suggested-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220323094307.2439004-1-ankit.k.nautiyal@intel.com