drm/i915: Fix double unref in intelfb_alloc failure path

In intelfb_alloc(), if the call to intel_pin_and_fence_fb_obj() fails,
the bo is unrefed twice: By drm_framebuffer_remove() and once more by
drm_gem_object_unreference(). Fix it.
Reported-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/cd7b33330621a350b0159ec5e098297b139cfaf7.1446892879.git.lukas@wunner.deSigned-off-by: NJani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/intel_fbdev.c

@@ -156,8 +156,9 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 
 	fb = __intel_framebuffer_create(dev, &mode_cmd, obj);
 	if (IS_ERR(fb)) {
+		drm_gem_object_unreference(&obj->base);
 		ret = PTR_ERR(fb);
-		goto out_unref;
+		goto out;
 	}
 
 	/* Flush everything out, we'll be doing GTT only from now on */
@@ -173,8 +174,6 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 
 out_fb:
 	drm_framebuffer_remove(fb);
-out_unref:
-	drm_gem_object_unreference(&obj->base);
 out:
 	return ret;
 }