8328812: Update and move siphash license

Backport-of: ce7ebaa606f96fdfee66d300b56022d9903b5ae3

Author: JesperIRL

src/hotspot/share/legal/siphash.md renamed to src/java.base/share/legal/siphash.md

@@ -4,12 +4,12 @@
 SipHash reference C implementation
 
 ```
-   Copyright (c) 2012-2021 Jean-Philippe Aumasson
-   <jeanphilippe.aumasson@gmail.com>
-   Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to>
+   Copyright (c) 2016 Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
+
    To the extent possible under law, the author(s) have dedicated all copyright
    and related and neighboring rights to this software to the public domain
    worldwide. This software is distributed without any warranty.
+
    You should have received a copy of the CC0 Public Domain Dedication along
    with
    this software. If not, see