drm/xe: Use migrate engine for page fault binds

We must use migrate engine for page fault binds in order to avoid a
deadlock as the migrate engine has a reserved BCS instance which cannot
be stuck on a fault. To use the migrate engine the engine argument to
xe_migrate_update_pgtables must be NULL, this was incorrectly wired up
so vm->eng[tile_id] was always being used. Fix this.
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_pt.c

@@ -1421,8 +1421,7 @@ __xe_pt_bind_vma(struct xe_tile *tile, struct xe_vma *vma, struct xe_engine *e,
 	}
 
 	fence = xe_migrate_update_pgtables(tile->migrate,
-					   vm, xe_vma_bo(vma),
-					   e ? e : vm->eng[tile->id],
+					   vm, xe_vma_bo(vma), e,
 					   entries, num_entries,
 					   syncs, num_syncs,
 					   &bind_pt_update.base);

drivers/gpu/drm/xe/xe_vm.c

@@ -1675,7 +1675,8 @@ xe_vm_bind_vma(struct xe_vma *vma, struct xe_engine *e,
 		if (!(vma->tile_mask & BIT(id)))
 			goto next;
 
-		fence = __xe_pt_bind_vma(tile, vma, e, first_op ? syncs : NULL,
+		fence = __xe_pt_bind_vma(tile, vma, e ? e : vm->eng[id],
+					 first_op ? syncs : NULL,
 					 first_op ? num_syncs : 0,
 					 vma->tile_present & BIT(id));
 		if (IS_ERR(fence)) {