x86-64: add "local_apic_timer_c2_ok" here too

Needed for any architecture that claims ARCH_APICTIMER_STOPS_ON_C3,
not just i386.

I'm hoping Thomas will clean this up a bit later..

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 09640a8..ef2ffded 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -780,7 +780,7 @@
 	lapic		[IA-32,APIC] Enable the local APIC even if BIOS
 			disabled it.
 
-	lapic_timer_c2_ok	[IA-32,APIC] trust the local apic timer in
+	lapic_timer_c2_ok	[IA-32,x86-64,APIC] trust the local apic timer in
 			C2 power state.
 
 	lasi=		[HW,SCSI] PARISC LASI driver for the 53c700 chip