staging:iio:adis16209: Set self_test_no_autoclear flag

The ADIS16201 does not automatically clear the self test flag bit the self
test has been, so clear it manually. Otherwise we'll see a offset caused by
the self-test bias on the output values during normal operation.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/accel/adis16209_core.c

@@ -168,6 +168,7 @@ static const struct adis_data adis16209_data = {
 	.diag_stat_reg = ADIS16209_DIAG_STAT,
 
 	.self_test_mask = ADIS16209_MSC_CTRL_SELF_TEST_EN,
+	.self_test_no_autoclear = true,
 	.startup_delay = ADIS16209_STARTUP_DELAY,
 
 	.status_error_msgs = adis16209_status_error_msgs,