delete unused IOCTLs ACCELIOCSSAMPLERATE and ACCEL_SAMPLERATE_DEFAULT

src/drivers/imu/adis16477/ADIS16477.cpp

@@ -407,10 +407,6 @@ ADIS16477::ioctl(struct file *filp, int cmd, unsigned long arg)
 
 		return 1000000 / _call_interval;
 
-	case ACCELIOCSSAMPLERATE:
-		_set_sample_rate(arg);
-		return OK;
-
 	case ACCELIOCSSCALE: {
 			/* copy scale, but only if off by a few percent */
 			struct accel_calibration_s *s = (struct accel_calibration_s *) arg;