[Blackfin] arch: Support for CPU_FREQ and NOHZ

Singed-off-by: Vitja Makarov <vitja.makarov@gmail.com>

include/asm-blackfin/time.h

@@ -24,6 +24,8 @@
 
 #ifndef CONFIG_CPU_FREQ
 #define TIME_SCALE 1
+#define __bfin_cycles_off (0)
+#define __bfin_cycles_mod (0)
 #else
 /*
  * Blackfin CPU frequency scaling supports max Core Clock 1, 1/2 and 1/4 .
@@ -31,6 +33,8 @@
  * adjust the Core Timer Presale Register. This way we don't lose time.
  */
 #define TIME_SCALE 4
+extern unsigned long long __bfin_cycles_off;
+extern unsigned int __bfin_cycles_mod;
 #endif
 
 #endif