x86-64: Move irq stats from PDA to per-cpu and consolidate with 32-bit.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 3973e2d..8b30d0c 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -36,11 +36,7 @@
 #endif
 }
 
-#ifdef CONFIG_X86_32
-# define irq_stats(x)		(&per_cpu(irq_stat, x))
-#else
-# define irq_stats(x)		cpu_pda(x)
-#endif
+#define irq_stats(x)		(&per_cpu(irq_stat, x))
 /*
  * /proc/interrupts printing:
  */