This package appears to include a private copy of valgrind.h. In the latest relase of valgrind 3.10.0 a bug was fixed for ppc32 and support was added for aarch64 and ppc64le. Please either update the private copy of valgrind.h (memcheck.h, callgrind.h, etc) or (better) make your package BuildRequires: valgrind-devel and use the system installed headers.
valgrind.h in mongodb is in bundled v8 and gperftool packages. But mongodb is builded using system versions of this packages. This problem in system versions is reported here: bug 1141483 and bug 1141472 Closing as NOTABUG, but if someone disagrees please reopen.