iio: proximity: hx9023s: Protect against division by zero in set_samp_freq

iio: proximity: hx9023s: Protect against division by zero in set_samp_freq

commit a318cfc0853706f1d6ce682dba660bc455d674ef upstream.

Avoid division by zero when sampling frequency is unspecified.

Fixes: 60df548277b7 ("iio: proximity: Add driver support for TYHX's HX9023S capacitive proximity sensor")
Signed-off-by: Yasin Lee <yasin.lee.x@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>