x86/tsc: Mark cyc2ns_init() and detect_art() __init

These two functions are only called by tsc_init(), which is an __init
function during boot time, so mark them __init as well.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1510135792-17429-1-git-send-email-douly.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/tsc.c

@@ -112,7 +112,7 @@ static void cyc2ns_data_init(struct cyc2ns_data *data)
 	data->cyc2ns_offset = 0;
 }
 
-static void cyc2ns_init(int cpu)
+static void __init cyc2ns_init(int cpu)
 {
 	struct cyc2ns *c2n = &per_cpu(cyc2ns, cpu);
 
@@ -955,7 +955,7 @@ core_initcall(cpufreq_register_tsc_scaling);
 /*
  * If ART is present detect the numerator:denominator to convert to TSC
  */
-static void detect_art(void)
+static void __init detect_art(void)
 {
 	unsigned int unused[2];