enabling CONFIG_FIT_SIGNATURE breaks U-Boot

[Rasmus Villemoes]

I'm trying to enable verified boot on an mpc8309, but the first step of
simply enabling CONFIG_FIT_SIGNATURE causes this:

[2020-02-07 17:23:34.342] U-Boot 2020.01-00037-g6e82ca3d2e (Feb 07 2020
- 17:23:16 +0100)
[2020-02-07 17:23:34.379]
[2020-02-07 17:23:34.379] Error binding driver 'mpc83xx_cpu': -12
[2020-02-07 17:23:34.379] Some drivers failed to bind
[2020-02-07 17:23:34.379] Reset Status: External/Internal Hard
[2020-02-07 17:23:34.380]
[2020-02-07 17:23:34.380] initcall sequence 000975a4 failed at call
00016d24 (err=-19)
[2020-02-07 17:23:34.380] ### ERROR ### Please RESET the board ###

00016d24 is <print_cpuinfo>, so I'm guessing that just fails due to the
earlier error of mpc83xx_cpu failing to bind with -ENOMEM. But I can't
figure out why just enabling CONFIG_FIT_SIGNATURE would have that
dramatic an effect. I probably need to adjust some other config
settings, but which?

Thanks,
Rasmus