CVE-2026-98660: iio: pressure: bmp280: fix out-of-bounds access in sampling frequency lookup

In the Linux kernel, the following vulnerability has been resolved: iio: pressure: bmp280: fix out-of-bounds access in sampling frequency lookup The sampling frequency tables store each frequency as an integer part and a fractional part in micro units. num_sampling_freq_avail is initialized to the number of flattened integer elements because read_avail() returns the table as a flat array. bmp280_write_sampling_frequency(), however, indexes the same table as a two-dimensional array and uses num_sampling_freq_avail as the number of rows. Convert the flattened element count back to the number of rows before iterating over the table.