PORT JRCU from Kernel 3.2.5-XPerience-18 from NEXUS 7
JRCU: Joe's RCU

 * The main purpose of jRCU is to bring together and execute on a single
 * CPU the RCU end-of-batch operations of all CPUs.  This relieves all but
 * one CPU from this periodic responsibility. This is important when the
 * system has user supplied realtime applications that require the full
 * use of CPUs dedicated to those applications.

Signed-off-by: Carlos Jesús <xxx.reptar.rawrr.xxx@gmail.com>