ANDROID: GKI: enable RCU configs

Enable configs needed for RCU perf/power optimizations

CONFIG_RCU_EXPERT=y
CONFIG_RCU_FAST_NO_HZ=y
CONFIG_RCU_NOCB_CPU=y

Bug: 162753392
Signed-off-by: Todd Kjos <tkjos@google.com>
Change-Id: Ie261e9dbd679c2f2481ebc1187c0ac4a01fd0767