ARM: mach-s3c64xx: use standard arch_idle() implementation

Signed-off-by: nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

arch/arm/mach-s3c64xx/include/mach/system.h

@@ -13,7 +13,7 @@
 
 static void arch_idle(void)
 {
-	/* nothing here yet */
+	cpu_do_idle();
 }
 
 #endif /* __ASM_ARCH_IRQ_H */