soc/tegra: Stub out PCIe IRQ workaround on 64-bit ARM

The PCIe host controller found on Tegra20 has a hardware bug that causes
PCIe interrupts to get lost when LP2 is enabled. Stub out the workaround
on 64-bit ARM because none of the more recent Tegra SoC generations seem
to have this bug anymore.
Signed-off-by: Thierry Reding <treding@nvidia.com>

include/soc/tegra/cpuidle.h

@@ -14,7 +14,7 @@
 #ifndef __SOC_TEGRA_CPUIDLE_H__
 #define __SOC_TEGRA_CPUIDLE_H__
 
-#ifdef CONFIG_CPU_IDLE
+#if defined(CONFIG_ARM) && defined(CONFIG_CPU_IDLE)
 void tegra_cpuidle_pcie_irqs_in_use(void);
 #else
 static inline void tegra_cpuidle_pcie_irqs_in_use(void)