util: Test __PPC64__ for getting PIPE_ARCH_PPC_64 respond to __PPC64__ take effect
Fixes: e737a99a ("Fix PPC detection on darwin") Signed-off-by:Yonggang Luo <luoyonggang@gmail.com> Reviewed-by:
Marek Olšák <marek.olsak@amd.com> Part-of: <mesa/mesa!19674>