drm/xe: Implement recent spec updates to Wa_16025250150

drm/xe: Implement recent spec updates to Wa_16025250150

The hardware teams noticed that the originally documented workaround
steps for Wa_16025250150 may not be sufficient to fully avoid a hardware
issue.  The workaround documentation has been augmented to suggest
programming one additional register; make the corresponding change in
the driver.

Fixes: 7654d51f1fd8 ("drm/xe/xe2hpg: Add Wa_16025250150")
Reviewed-by: Matt Atwood <matthew.s.atwood@intel.com>
Link: https://patch.msgid.link/20260319-wa_16025250150_part2-v1-1-46b1de1a31b2@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>