drm/xe/mtl: Fix PAT table coherency settings

Re-sync our MTL PAT table with the bspec.  1-way coherency should only
be set on table entry 3.  We do not want an incorrect setting here to
accidentally paper over other bugs elsewhere in the driver.

Bspec: 45101
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Link: https://lore.kernel.org/r/20230324210415.2434992-6-matthew.d.roper@intel.com


Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>