drm/i915/hdmi: SPD infoframe update for discrete

Replace integrated with discrete for dgfx platforms.

v2: commit title reword (Jani)
v3: use variable name i915 (Jani)
v4: commit message reword (MattR)

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Taylor, Clinton A <clinton.a.taylor@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221129203343.720860-1-clinton.a.taylor@intel.com