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.
*** Bug 1141580 has been marked as a duplicate of this bug. ***
ipxe is x86 only AIUI, so updating to accomodate non-x86 archs isn't important. The ipxe git log says adding the headers was explicitly to avoid a dependency on valgrind, so I doubt changing that now would fly upstream. Closing as WONTFIX, but if someone disagrees please reopen