util_libs: license clarification

This file was mistakenly tagged as GPL, when it should be BSD. Commit
a7130f9f836 previously already fixed the license text, but not the tag,
which in the SPDX conversion then got lost.

Signed-off-by: Gerwin Klein <gerwin.klein@proofcraft.systems>

libutils/include/utils/config.h

diff --git a/libutils/include/utils/config.h b/libutils/include/utils/config.h
index 3340af4..0078bc2 100644
--- a/libutils/include/utils/config.h
+++ b/libutils/include/utils/config.h
@@ -1,7 +1,7 @@
 /*
  * Copyright 2017, Data61, CSIRO (ABN 41 687 119 230)
  *
- * SPDX-License-Identifier: GPL-2.0-only
+ * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #pragma once