rcu/update: Convert to SPDX license identifier

Replace the license boiler plate with a SPDX license identifier.
While in the area, update an email address.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Paul E. McKenney 2019-01-17 10:25:18 -08:00
commit 38b4df649e