If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_needs_cpu() will always
return false, however, the current version nevertheless checks
for RCU callbacks.  This commit therefore creates a static inline
implementation of rcu_needs_cpu() that unconditionally returns false
when CONFIG_RCU_NOCB_CPU_ALL=y.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>