drm/i915: simplify swapin/out swizzle checking a bit

Use the helper function already employed by the pwrite/pread
functions.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index f0f885f..d8e0c15 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1476,7 +1476,7 @@
 		obj->pages[i] = page;
 	}
 
-	if (obj->tiling_mode != I915_TILING_NONE)
+	if (i915_gem_object_needs_bit17_swizzle(obj))
 		i915_gem_object_do_bit_17_swizzle(obj);
 
 	return 0;
@@ -1498,7 +1498,7 @@
 
 	BUG_ON(obj->madv == __I915_MADV_PURGED);
 
-	if (obj->tiling_mode != I915_TILING_NONE)
+	if (i915_gem_object_needs_bit17_swizzle(obj))
 		i915_gem_object_save_bit_17_swizzle(obj);
 
 	if (obj->madv == I915_MADV_DONTNEED)