drm/i915/dg1: invert HPD pins

HPD pins are inverted for DG1 platform.

Bspec: 49956
Cc: José Roberto de Souza <jose.souza@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Clinton A Taylor <clinton.a.taylor@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201021082034.3170478-3-lucas.demarchi@intel.com