iio: dac: ad3552r: change AD3552R_NUM_CH define name

iio: dac: ad3552r: change AD3552R_NUM_CH define name

After model data and num_hw_channles introduction, we have:

ad3552r_desc, num_ch: used to keep channel number set in fdt,
ad35xxr_model_data, num_hw_channels: for max channel checks,
AD3552R_NUM_CH: just actually used to define the max array size
on allocated arrays.

Renaming AD3552R_NUM_CH to a more consistent name, as AD3552R_MAX_CH.

Signed-off-by: Angelo Dureghello <adureghello@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240522150141.1776196-6-adureghello@baylibre.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>