rcu: Fix pr_info() formats and values in show_rcu_gp_kthreads()

This commit changes from "%lx" to "%x" and from "0x1ffffL" to "0x1ffff"
to match the change in type between the old field ->state (unsigned long)
and the new field ->__state (unsigned int).

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>