Merge remote-tracking branch 'remotes/quic/tmp-bf4ce20b' into LA.BR.1.2.5

This commit brings in some rcu changes from upstream to fix some
rcu issues like boot up getting delay upto 300 seconds, etc.

* remotes/quic/tmp-bf4ce20b:
  rcu: Use rcu_gp_kthread_wake() to wake up grace period kthreads
  rcu: Check both root and current rcu_node when setting up future grace period
  rcu: Make callers awaken grace-period kthread
  rcu: Update cpu_needs_another_gp() for futures from non-NOCB CPUs
  rcu: Protect ->gp_flags accesses with ACCESS_ONCE()
  nohz_full: Force RCU's grace-period kthreads onto timekeeping CPU
  rcu: Throttle rcu_try_advance_all_cbs() execution
  rcu: Flag lockless access to ->gp_flags with ACCESS_ONCE()
  rcu: Prevent spurious-wakeup DoS attack on rcu_gp_kthread()
  rcu: Avoid redundant grace-period kthread wakeups
  rcu: Move redundant call to note_gp_changes() into called function
  rcu: Inline trivial wrapper function rcu_start_gp_per_cpu()
  rcu: Eliminate check_for_new_grace_period() wrapper function
  rcu: Merge __rcu_process_gp_end() into __note_gp_changes()
  rcu: Switch callers from rcu_process_gp_end() to note_gp_changes()
  rcu: Rename note_new_gpnum() to note_gp_changes()
  rcu: Make __note_new_gpnum() check for ends of prior grace periods
  rcu: Move code to apply callback-numbering simplifications
  rcu: Fix missing task information during rcu-preempt stall
  rcu: Add GP-kthread-starvation checks to CPU stall warnings
  rcu: Make RCU_CPU_STALL_INFO include number of fqs attempts
  rcu: Improve diagnostics for spurious RCU CPU stall warnings
  rcu: Move RCU-related source code to kernel/rcu directory

Change-Id: I96b6d465af3360e287055417c1399905061b985a
Signed-off-by: Kishan Kumar <kishank@codeaurora.org>