drm/i915/dram: Use intel_dram_type_str() for pnv

Replace the hand rolled PNV memory type printk string
stuff with intel_dram_type_str().

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250902133113.18778-3-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>