Revert "Revert "poky: subtree update:b23aa6b753..ad30a6d470""

This reverts commit 4873add6e11c1bd421c83cd08df589f1184aa673.

A fix has been put up for openbmc/openbmc#3720 so we can bring
this back now

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: If59020a5b502f70aa7149fbef4ad2f50824d1ce6
diff --git a/poky/documentation/ref-manual/ref-system-requirements.rst b/poky/documentation/ref-manual/ref-system-requirements.rst
index 56218e4..54f38f6 100644
--- a/poky/documentation/ref-manual/ref-system-requirements.rst
+++ b/poky/documentation/ref-manual/ref-system-requirements.rst
@@ -1,4 +1,4 @@
-.. SPDX-License-Identifier: CC-BY-2.0-UK
+.. SPDX-License-Identifier: CC-BY-SA-2.0-UK
 
 *******************
 System Requirements