arm: Remove unused cpu_idle_wait()

cpuidle uses a generic function now. Remove the unused code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Link: http://lkml.kernel.org/r/20120507175652.260797846@linutronix.de

arch/arm/include/asm/processor.h

@@ -88,8 +88,6 @@ unsigned long get_wchan(struct task_struct *p);
 #define cpu_relax()			barrier()
 #endif
 
-void cpu_idle_wait(void);
-
 /*
  * Create a new kernel thread
  */