nohz: Remove obsolete check for full dynticks CPUs to be RCU nocbs

Building full dynticks now implies that all CPUs are forced
into RCU nocb mode through CONFIG_RCU_NOCB_CPU_ALL.

The dynamic check has become useless.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>

kernel/time/tick-sched.c

@@ -351,16 +351,6 @@ void __init tick_nohz_init(void)
 	}
 
 	cpu_notifier(tick_nohz_cpu_down_callback, 0);
-
-	/* Make sure full dynticks CPU are also RCU nocbs */
-	for_each_cpu(cpu, nohz_full_mask) {
-		if (!rcu_is_nocb_cpu(cpu)) {
-			pr_warning("NO_HZ: CPU %d is not RCU nocb: "
-				   "cleared from nohz_full range", cpu);
-			cpumask_clear_cpu(cpu, nohz_full_mask);
-		}
-	}
-
 	cpulist_scnprintf(nohz_full_buf, sizeof(nohz_full_buf), nohz_full_mask);
 	pr_info("NO_HZ: Full dynticks CPUs: %s.\n", nohz_full_buf);
 }