drm/xe/mtl: Drop pre-prod workarounds Wa_14015795083 & Wa_14014475959

drm/xe/mtl: Drop pre-prod workarounds Wa_14015795083 & Wa_14014475959

Wa_14015795083 and Wa_14014475959 only apply to early steppings of
Xe_LPG that appeared only in pre-production hardware (in fact
Wa_14014475959 wasn't supposed to apply to _any_ steppings of version
12.71).  Xe1 platforms already aren't officially supported by the Xe
driver, but pre-production steppings are especially out of scope (and
'has_pre_prod_wa' is not set in the device descriptor).  Drop both
workarounds.

Bspec: 55420
Reviewed-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@intel.com>
Link: https://patch.msgid.link/20260220-forupstream-wa_cleanup-v2-1-b12005a05af6@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>