armv7, this should save around 40h overall build time, and makes it more
visible to anyone working on the port that they are indeed broken on the
arch. OK phessler@ naddy@
Of note because the port is important to the architecture and
self-hosted builds are a good thing: building u-boot on armv7 fails
with an Internal Compiler Error (SIGBUS) in lib/time.c, it would be
particularly nice if someone has an idea how to fix this!