[SPARC64]: Add sun4v_cpu_yield().

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/asm-sparc64/hypervisor.h b/include/asm-sparc64/hypervisor.h
index cd5fbcd..726e2ea0 100644
--- a/include/asm-sparc64/hypervisor.h
+++ b/include/asm-sparc64/hypervisor.h
@@ -258,6 +258,9 @@
  */
 #define HV_FAST_CPU_YIELD		0x12
 
+#ifndef __ASSEMBLY__
+extern unsigned long sun4v_cpu_yield(void);
+#endif
 
 /* cpu_qconf()
  * TRAP:	HV_FAST_TRAP