rcu: Use new nesting value for rcu_dyntick trace in rcu_eqs_enter_common

This patch uses the real new value of dynticks_nesting instead of 0 in
rcu_eqs_enter_common().

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>