drm/i915: Reclassify SKL 0x192a as GT3

Reclassify 0x192A according to specifications. Of note, the
second to last digit seems to correspond to GT#.

Signed-off-by: Alexei Podtelezhnikov <apodtele@gmail.com>
[vsyrjala: Split separate changes into separate patches]
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200716172106.2656-3-ville.syrjala@linux.intel.com


Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>