preempt: Make PREEMPT_ACTIVE generic

No point in having this bit defined by architecture.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130917183629.090698799@linutronix.de

arch/xtensa/include/asm/thread_info.h

@@ -76,8 +76,6 @@ struct thread_info {
 
 #endif
 
-#define PREEMPT_ACTIVE		0x10000000
-
 /*
  * macros/functions for gaining access to the thread information structure
  */