drm/i915/migrate: fix offset calculation

Ensure we add the engine base only after we calculate the qword offset
into the PTE window.
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211206112539.3149779-2-matthew.auld@intel.com

drivers/gpu/drm/i915/gt/intel_migrate.c

@@ -279,10 +279,10 @@ static int emit_pte(struct i915_request *rq,
 	GEM_BUG_ON(GRAPHICS_VER(rq->engine->i915) < 8);
 
 	/* Compute the page directory offset for the target address range */
-	offset += (u64)rq->engine->instance << 32;
 	offset >>= 12;
 	offset *= sizeof(u64);
 	offset += 2 * CHUNK_SZ;
+	offset += (u64)rq->engine->instance << 32;
 
 	cs = intel_ring_begin(rq, 6);
 	if (IS_ERR(cs))