ARM: 8644/1: Reduce "CPU: shutdown" message to debug level

Similar to c68b0274 ("ARM: reduce "Booted secondary processor"
message to debug level"), demote the "CPU: shutdown" pr_notice() into a
pr_debug().
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/smp.c

@@ -251,7 +251,7 @@ void __cpu_die(unsigned int cpu)
 		pr_err("CPU%u: cpu didn't die\n", cpu);
 		return;
 	}
-	pr_notice("CPU%u: shutdown\n", cpu);
+	pr_debug("CPU%u: shutdown\n", cpu);
 
 	/*
 	 * platform_cpu_kill() is generally expected to do the powering off