iio: common: scmi_iio: use kcalloc() instead of kzalloc()

iio: common: scmi_iio: use kcalloc() instead of kzalloc()

Replace calls of devm_kzalloc() with devm_kcalloc() in scmi_alloc_iiodev()
and scmi_iio_set_sampling_freq_avail() for safer memory allocation with
built-in overflow protection.

Similarly, use array_size() instead of explicit multiplication for
'sensor->sensor_info->intervals.count * 2'.

Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://patch.msgid.link/20250819125017.635182-1-rongqianfeng@vivo.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>