x86: fix up a comment in ack_APIC_irq()

 Adjust a comment in ack_APIC_irq() according to the recent removal of
CONFIG_X86_GOOD_APIC.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/asm-x86/apic.h

@@ -76,9 +76,7 @@ extern int get_physical_broadcast(void);
 static inline void ack_APIC_irq(void)
 {
 	/*
-	 * ack_APIC_irq() actually gets compiled as a single instruction:
-	 * - a single rmw on Pentium/82489DX
-	 * - a single write on P6+ cores (CONFIG_X86_GOOD_APIC)
+	 * ack_APIC_irq() actually gets compiled as a single instruction
 	 * ... yummie.
 	 */