Update buildroot

Pick buildroot's cesnet/2024-01-10 branch which cherry-picks two
buildroot commits fixing possible local build failures [1,2].

* 4de60e41 ("package/host-gdb: disable source-highlight")
* 9ba399a3 ("package/gdb: disable source-highlight")

[1] https://github.com/buildroot/buildroot/commit/4de60e41c3487946712da6d889ef89d325c2032a
[2] https://github.com/buildroot/buildroot/commit/9ba399a3ddfc3129c5334c558b52665053a932cb

Change-Id: Ie54fafb5dd90b40fe4d85fa3c8d04dca0134a2bd
diff --git a/submodules/buildroot b/submodules/buildroot
index 473753e..564081e 160000
--- a/submodules/buildroot
+++ b/submodules/buildroot
@@ -1 +1 @@
-Subproject commit 473753ed36d0ea2870f6a57d95e713fe8e17b350
+Subproject commit 564081e607e8bd776d78232da4c6a516e71dbb33