drm/i915/dram: Fix some spelling around the 16Gb DIMM w/a

drm/i915/dram: Fix some spelling around the 16Gb DIMM w/a

Use consistent spelling when talking about the 16Gb DIMM w/a.

Even currently language is a bit off as the w/a is actually
about DIMMs with 16Gb DRAM devices on them, not the total capacity
of the whole DIMM. But this language does more or less match how
Bspec talks about this stuff.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250902133113.18778-7-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>