tests/driver_bq2429x: fix implicit conversion in helper function
tests/driver_bq2429x: fix implicit conversion in helper function

The parameter expects a bq2429x_chrg_fault_t but is declared as bq2429x_chrg_stat_t

ant9000/RIOT,jasonatran/RIOT,authmillenon/RIOT,authmillenon/RIOT,jasonatran/RIOT,authmillenon/RIOT,authmillenon/RIOT,miri64/RIOT,OTAkeys/RIOT,kaspar030/RIOT,OTAkeys/RIOT,kYc0o/RIOT,miri64/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,miri64/RIOT,RIOT-OS/RIOT,OTAkeys/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,OlegHahm/RIOT,ant9000/RIOT,ant9000/RIOT,ant9000/RIOT,kYc0o/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,miri64/RIOT,OlegHahm/RIOT,miri64/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,OlegHahm/RIOT,jasonatran/RIOT,kYc0o/RIOT,authmillenon/RIOT,jasonatran/RIOT,OTAkeys/RIOT,kaspar030/RIOT,OTAkeys/RIOT,ant9000/RIOT,authmillenon/RIOT,kYc0o/RIOT,kaspar030/RIOT