drm/i915: Repack fence tiling mode and stride into a single integer

In the previous commit, we moved the obj->tiling_mode out of a bitfield
and into its own integer so that we could safely use READ_ONCE(). Let us
now repair some of that damage by sharing the tiling_mode with its
companion, the fence stride.

v2: New magic

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470388464-28458-18-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 1faea38..0620a84 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -101,7 +101,7 @@
 
 static char get_tiling_flag(struct drm_i915_gem_object *obj)
 {
-	switch (obj->tiling_mode) {
+	switch (i915_gem_object_get_tiling(obj)) {
 	default:
 	case I915_TILING_NONE: return ' ';
 	case I915_TILING_X: return 'X';