processor: remove spin_cpu_yield

spin_cpu_yield is unused, therefore remove it.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

arch/powerpc/include/asm/processor.h

@@ -346,8 +346,6 @@ static inline unsigned long __pack_fe01(unsigned int fpmode)
 
 #define spin_cpu_relax()	barrier()
 
-#define spin_cpu_yield()	spin_cpu_relax()
-
 #define spin_end()	HMT_medium()
 
 #define spin_until_cond(cond)					\

include/linux/processor.h

@@ -32,15 +32,6 @@
 #define spin_cpu_relax() cpu_relax()
 #endif
 
-/*
- * spin_cpu_yield may be called to yield (undirected) to the hypervisor if
- * necessary. This should be used if the wait is expected to take longer
- * than context switch overhead, but we can't sleep or do a directed yield.
- */
-#ifndef spin_cpu_yield
-#define spin_cpu_yield() cpu_relax_yield()
-#endif
-
 #ifndef spin_end
 #define spin_end()
 #endif