Speed 24 MHz - not 24 Hz for Lowest voltage

teensy4/clockspeed.c

 			if (voltage > OVERCLOCK_MAX_VOLT) voltage = OVERCLOCK_MAX_VOLT;
 		}
 #endif
-	} else if (frequency <= 24) {
+	} else if (frequency <= 24000000) {
 		voltage = 950; // 0.95
 	}