iio: adc: ad7124: fix division by zero in ad7124_set_channel_odr()

In the Linux kernel, the following vulnerability has been resolved:

iio: adc: ad7124: fix division by zero in ad7124_set_channel_odr()

In the ad7124_write_raw() function, parameter val can potentially

be zero. This may lead to a division by zero when DIV_ROUND_CLOSEST()

is called within ad7124_set_channel_odr(). The ad7124_write_raw()

function is invoked through the sequence: iio_write_channel_raw() ->

iio_write_channel_attribute() -> iio_channel_write(), with no checks

in place to ensure val is non-zero.