ARM: tegra: Avoid compiling cpuidle code when not configured

No need to compile cpuidle.c and sleep.S if cpuidle isn't configured in the
kernel.
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/mach-tegra/Makefile

@@ -7,8 +7,8 @@ obj-y                                   += clock.o
 obj-y                                   += timer.o
 obj-y                                   += pinmux.o
 obj-y					+= fuse.o
-obj-y					+= cpuidle.o
-obj-y					+= sleep.o
+obj-$(CONFIG_CPU_IDLE)			+= cpuidle.o
+obj-$(CONFIG_CPU_IDLE)			+= sleep.o
 obj-$(CONFIG_ARCH_TEGRA_2x_SOC)		+= powergate.o
 obj-$(CONFIG_ARCH_TEGRA_2x_SOC)         += tegra2_clocks.o
 obj-$(CONFIG_ARCH_TEGRA_2x_SOC)		+= tegra2_emc.o