drm/xe/migrate: fix pat index usage

XE_CACHE_WB must be converted into the per-platform pat index for that
particular caching mode, otherwise we are just encoding whatever happens
to be the value of that enum.

Fixes: e8babb2 ("drm/xe: Convert multiple bind ops into single job")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Nirmoy Das <nirmoy.das@intel.com>
Cc: <stable@vger.kernel.org> # v6.12+
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241126181259.159713-3-matthew.auld@intel.com
(cherry picked from commit f3dc924)
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Author: matt-auld

drivers/gpu/drm/xe/xe_migrate.c

@@ -1350,6 +1350,7 @@ __xe_migrate_update_pgtables(struct xe_migrate *m,
 
 	/* For sysmem PTE's, need to map them in our hole.. */
 	if (!IS_DGFX(xe)) {
+		u16 pat_index = xe->pat.idx[XE_CACHE_WB];
 		u32 ptes, ofs;
 
 		ppgtt_ofs = NUM_KERNEL_PDE - 1;
@@ -1409,7 +1410,7 @@ __xe_migrate_update_pgtables(struct xe_migrate *m,
 						pt_bo->update_index = current_update;
 
 					addr = vm->pt_ops->pte_encode_bo(pt_bo, 0,
-									 XE_CACHE_WB, 0);
+									 pat_index, 0);
 					bb->cs[bb->len++] = lower_32_bits(addr);
 					bb->cs[bb->len++] = upper_32_bits(addr);
 				}