Only implement HSRUN changes when F_CPU > 120 MHz

teensy3/kinetis.h

 #endif
 extern int nvic_execution_priority(void);
 
-#ifdef HAS_KINETIS_HSRUN
+#if defined(HAS_KINETIS_HSRUN) && F_CPU > 120000000
 extern int kinetis_hsrun_disable(void);
 extern int kinetis_hsrun_enable(void);
 #else

teensy3/mk20dx128.c

 }
 
 
-#ifdef HAS_KINETIS_HSRUN
+#if defined(HAS_KINETIS_HSRUN) && F_CPU > 120000000
 int kinetis_hsrun_disable(void)
 {
 	if (SMC_PMSTAT == SMC_PMSTAT_HSRUN) {
 	}
 	return 0;
 }
-#endif // HAS_KINETIS_HSRUN
+#endif // HAS_KINETIS_HSRUN && F_CPU > 120000000