drm/i915: Use intel_fb_obj() everywhere

We already have a macro to pull the GEM object from a FB, so use it
everywhere. We'll make use of this later to move the object storage.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20180518143008.4120-1-daniels@collabora.com

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1908,7 +1908,7 @@ static int i915_gem_framebuffer_info(struct seq_file *m, void *data)
 			   fbdev_fb->base.format->cpp[0] * 8,
 			   fbdev_fb->base.modifier,
 			   drm_framebuffer_read_refcount(&fbdev_fb->base));
-		describe_obj(m, fbdev_fb->obj);
+		describe_obj(m, intel_fb_obj(&fbdev_fb->base));
 		seq_putc(m, '\n');
 	}
 #endif
@@ -1926,7 +1926,7 @@ static int i915_gem_framebuffer_info(struct seq_file *m, void *data)
 			   fb->base.format->cpp[0] * 8,
 			   fb->base.modifier,
 			   drm_framebuffer_read_refcount(&fb->base));
-		describe_obj(m, fb->obj);
+		describe_obj(m, intel_fb_obj(&fb->base));
 		seq_putc(m, '\n');
 	}
 	mutex_unlock(&dev->mode_config.fb_lock);