CVE-2026-98667: iio: frequency: adf4377: Fully initialize clk_init_data and clk_parent_data

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

iio: frequency: adf4377: Fully initialize clkinitdata and clkparentdata

The clkinitdata structure contains several mutually-exclusive members for different methods to specify the possible parents of a clock, prompting drivers to initialize only the members they need. However, not initializing all members may cause subtle issues, which are only exposed when CONFIGINITSTACKALLPATTERN or CONFIGINITSTACKNONE is enabled.

adf4377clkregister() fills in init.parentdata, and assumes that init.parentnames is NULL. However, the latter is uninitialized, and thus may cause a crash.

Similarly, adf4377clkregister() fills in only parentdata.fwname, leaving other members of the clkparentdata structure uninitialized.

Make sure all members are fully initialized, to fix such bugs, and to avoid future breakage when converting drivers to a different method for specifying the parents.