powerpc: Fix powerpc64le due a7a3435c

The build uses an undefined macro evaluation for fmaf128 build.
For now set USE_FMAL_BUILTIN and USE_FMAF128_BUILTIN to 0.

Checked with a build for:

  powerpc64le-linux-gnu-power9-disable-multi-arch
  powerpc64le-linux-gnu-power9
  powerpc64le-linux-gnu
  powerpc64-linux-gnu-power8
  powerpc64-linux-gnu
  powerpc-linux-gnu-power4
  powerpc-linux-gnu