gma500: remove double free in psbfb_create

[Dave Jones <davej@redhat.com>]

This code appears to be calling psb_gtt_free_range twice with the same args.
(The second call didn't appear in the diff output, it's right after the mutex_unlock)

Spotted with Coverity, not tested due to lack of hardware.

Signed-off-by: Dave Jones <davej@fedoraproject.org>

diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
index 01dd7d2..d35ffc4 100644
--- a/drivers/gpu/drm/gma500/framebuffer.c
+++ b/drivers/gpu/drm/gma500/framebuffer.c
@@ -479,9 +479,7 @@ static int psbfb_create(struct psb_fbdev *fbdev,
 	mutex_unlock(&dev->struct_mutex);
 	return 0;
 out_unref:
-	if (backing->stolen)
-		psb_gtt_free_range(dev, backing);
-	else
+	if (!backing->stolen)
 		drm_gem_object_unreference(&backing->gem);
 out_err1:
 	mutex_unlock(&dev->struct_mutex);