Because rcu_eqs_special_set() is declared only in internal header
kernel/rcu/tree.h and stubbed in include/linux/rcutiny.h, it is
inaccessible outside of the RCU implementation.  This patch therefore
moves the  rcu_eqs_special_set() declaration to include/linux/rcutree.h,
which allows it to be used in non-rcu kernel code.
Signed-off-by: NYury Norov <ynorov@caviumnetworks.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: NNicholas Piggin <npiggin@gmail.com>