Add new variables to the per chip info structure:

* test_points: Number of valid test points for calibration;
* has_dco_invert: Supports inverting DCO (Data clock output) polarity;
* dco_en: Specicic mask to enable DCO delays.

This is in preparation for supporting new parts with subtle differences
in how to configure the hardware.

Note that with the new test_points variable, we also add a new
calib_map_size to 'struct ad9467_state' so we know our map size
depending on how many test points we have and if we can run the
calibration in the inverted state or not.
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20240704-dev-iio-ad9467-new-devs-v1-2-f1adfee921f7@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>