drm/i915/dp: Dump the LTTPR PHY descriptors

Dump the descriptor of the detected LTTPRs in non-transparent mode to
help the debugging related to LTTPRs easier.

v2: Use drm_dp_dump_lttpr_desc() instead of the driver specific
    equivalent.
v3: Add empty line between license and header section. (Ankit)
v4: Don't include drm_dp_helper.h twice. (Jani)

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> # v1
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240909135627.2926906-1-imre.deak@intel.com