FROMLIST: rcu: Provide a boot time parameter to control lazy RCU

To allow more flexible arrangements while still provide a single kernel
for distros, provide a boot time parameter to enable/disable lazy RCU.

Specify:

	rcutree.enable_rcu_lazy=[y|1|n|0]

Which also requires

	rcu_nocbs=all

at boot time to enable/disable lazy RCU.

To disable it by default at build time when CONFIG_RCU_LAZY=y, the new
CONFIG_RCU_LAZY_DEFAULT_OFF can be used.

Bug: 258241771
Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io>
Tested-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/lkml/20231203011252.233748-1-qyousef@layalina.io/


[Fix trivial conflicts rejecting newer code that doesn't exist on 5.15]
Signed-off-by: Qais Yousef <qyousef@google.com>
Change-Id: Ib5585ae717a2ba7749f2802101b785c4e5de8a90