staging:iio:adis16400: Remove samplerate_available attribute

While the samplerate supported by the devices which are supported by this driver
is not continuous it supports a wide range, much more than currently listed in
the samplerate_available attribute. Also it accepts all values written to the
samplerate attribute and will round-up them to the nearest supported sample
rate. So remove the samplerate_available attribute.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/imu/adis16400_core.c

@@ -247,8 +247,6 @@ static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
 			      adis16400_read_frequency,
 			      adis16400_write_frequency);
 
-static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("409 546 819 1638");
-
 static const u8 adis16400_addresses[] = {
 	[ADIS16400_SCAN_GYRO_X] = ADIS16400_XGYRO_OFF,
 	[ADIS16400_SCAN_GYRO_Y] = ADIS16400_YGYRO_OFF,
@@ -574,7 +572,6 @@ static const struct iio_chan_spec adis16334_channels[] = {
 
 static struct attribute *adis16400_attributes[] = {
 	&iio_dev_attr_sampling_frequency.dev_attr.attr,
-	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
 	NULL
 };