Comment # 1 on bug 1201204 from Michal Suchanek

Interestingly, the libc for the compiler is available on 15 SP3, only the
compiler is missing:

  | cross-arm-none-newlib-devel | package | 3.0.0-bp153.3.12 | ppc64le |
SUSE-PackageHub-15-SP3-Backports-Pool

Aggregating cross-arm-none-gcc7 from Leap 15.2 updates I can build ATF and
u-voot for rk3399 correctly.