Revert "[compiler-rt][CMake] Enable TF intrinsics on powerpc32 Linux"

As mentioned in https://reviews.llvm.org/D121379#3690593, this
change broke the build of compiler-rt targeting powerpc using GCC.
The 32-bit powerpc target is not supposed to emit 128-bit libcalls
-- if it does, then that's a backend bug and needs to be fixed there.

This reverts commit 8f24a56a.

Differential Revision: https://reviews.llvm.org/D130988

(cherry picked from commit 542977d4)