[U-Boot] buileman does not report error on qemu-x86_64

[Bin Meng]

Hi Simon, Henrich,

When I used buildman to build x86 targets, buildman did not complain
any error on qemu-x86_64.

But if I manually run 'make qemu-x86_64_defconfig;make', I get:

Node '/binman/u-boot-spl-with-ucode-ptr': Cannot locate
_dt_ucode_base_size symbol in u-boot

This is quite weird. I tried to roll back to some older version U-Boot
(like v2017.09), but the issue is still the same. Even if I reset the
commit to the very first version that introduced the qemu-x86_64
support, I still got the same build error.

Do you know anything that could cause this?

Regards,
Bin