x86: remove get_cycles_sync

rdtsc is now speculation-safe, so no need for the sync variants of
the APIs.

[ mingo@elte.hu: removed the nsec_barrier() complication. ]

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c
index 05d8f25..ace3405 100644
--- a/arch/x86/kernel/tsc_sync.c
+++ b/arch/x86/kernel/tsc_sync.c
@@ -46,7 +46,7 @@
 	cycles_t start, now, prev, end;
 	int i;
 
-	start = get_cycles_sync();
+	start = get_cycles();
 	/*
 	 * The measurement runs for 20 msecs:
 	 */
@@ -61,7 +61,7 @@
 		 */
 		__raw_spin_lock(&sync_lock);
 		prev = last_tsc;
-		now = get_cycles_sync();
+		now = get_cycles();
 		last_tsc = now;
 		__raw_spin_unlock(&sync_lock);