iio:pressure:ms5637: limit available sample frequencies

Avoid exposing all the sampling frequencies for chip that only support a
subset.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210109231148.1168104-4-alexandre.belloni@bootlin.com


Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>