ARM: mach-gemini: move special idle code out of line

... and hook it to arm_pm_idle.

Signed-off-by: nicolas Pitre <nicolas.pitre@linaro.org>
diff --git a/arch/arm/mach-gemini/irq.c b/arch/arm/mach-gemini/irq.c
index 9485a8f..ca70e5f 100644
--- a/arch/arm/mach-gemini/irq.c
+++ b/arch/arm/mach-gemini/irq.c
@@ -73,8 +73,8 @@
 	unsigned int i, mode = 0, level = 0;
 
 	/*
-	 * Disable arch_idle() by default since it is buggy
-	 * For more info see arch/arm/mach-gemini/include/mach/system.h
+	 * Disable the idle handler by default since it is buggy
+	 * For more info see arch/arm/mach-gemini/idle.c
 	 */
 	disable_hlt();