drm/vmwgfx: Fix user space handle equal to zero

commit 8407f8a1 upstream.

User-space handles equal to zero are interpreted as uninitialized or
illegal by some drm systems (most notably kms). This means that a
dumb buffer or surface with a zero user-space handle can never be
used as a kms frame-buffer.

Cc: <stable@vger.kernel.org>
Fixes: c7eae626 ("drm/vmwgfx: Make the object handles idr-generated")
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Deepak Rawat <drawat@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/vmwgfx/ttm_object.c

@@ -174,7 +174,7 @@ int ttm_base_object_init(struct ttm_object_file *tfile,
 	kref_init(&base->refcount);
 	idr_preload(GFP_KERNEL);
 	spin_lock(&tdev->object_lock);
-	ret = idr_alloc(&tdev->idr, base, 0, 0, GFP_NOWAIT);
+	ret = idr_alloc(&tdev->idr, base, 1, 0, GFP_NOWAIT);
 	spin_unlock(&tdev->object_lock);
 	idr_preload_end();
 	if (ret < 0)