ARM: tegra: cpuidle: using IS_ENABLED for multi SoCs management in init func

Clean up the Tegra CPUidle init function by using IS_ENABLED for multi
SoCs management in the init function.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
diff --git a/arch/arm/mach-tegra/cpuidle.h b/arch/arm/mach-tegra/cpuidle.h
index 9bcf61f..9ec2c1a 100644
--- a/arch/arm/mach-tegra/cpuidle.h
+++ b/arch/arm/mach-tegra/cpuidle.h
@@ -17,25 +17,10 @@
 #ifndef __MACH_TEGRA_CPUIDLE_H
 #define __MACH_TEGRA_CPUIDLE_H
 
-#ifdef CONFIG_ARCH_TEGRA_2x_SOC
-int tegra20_cpuidle_init(void);
-#else
-static inline int tegra20_cpuidle_init(void) { return -ENODEV; }
-#endif
-
-#ifdef CONFIG_ARCH_TEGRA_3x_SOC
-int tegra30_cpuidle_init(void);
-#else
-static inline int tegra30_cpuidle_init(void) { return -ENODEV; }
-#endif
-
-#ifdef CONFIG_ARCH_TEGRA_114_SOC
-int tegra114_cpuidle_init(void);
-#else
-static inline int tegra114_cpuidle_init(void) { return -ENODEV; }
-#endif
-
 #ifdef CONFIG_CPU_IDLE
+int tegra20_cpuidle_init(void);
+int tegra30_cpuidle_init(void);
+int tegra114_cpuidle_init(void);
 void tegra_cpuidle_init(void);
 #else
 static inline void tegra_cpuidle_init(void) {}