boot/xilinx-prebuilt: add hash for LICENSE file

Add hash for xilinx-prebuilt LICENSE file.

Signed-off-by: Neal Frager <neal.frager@amd.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

boot/xilinx-prebuilt/xilinx-prebuilt.hash

@@ -1,2 +1,5 @@
 # Locally calculated
 sha256  7abcba4e0e44e3a4adf9c1f971d918575226d7604dfd64a386baaa00c1c6c35f  xilinx-prebuilt-xilinx_v2024.1.tar.gz
+
+# Locally calculated
+sha256  7b2074b607264a07347e1a7ef0323229585942793469f34b2cf9628f7623e05f  LICENSE