Drop the not really supported PowerPC 32bit target

The LLVM backend has known issues and even for them the main
development target is PowerPC 64bit Little Endian.

Author: lu-zero

ci/dox.sh

@@ -40,7 +40,7 @@ dox i686 i686-unknown-linux-gnu
 dox x86_64 x86_64-unknown-linux-gnu
 dox arm armv7-unknown-linux-gnueabihf
 dox aarch64 aarch64-unknown-linux-gnu
-dox powerpc powerpc-unknown-linux-gnu
+# dox powerpc powerpc-unknown-linux-gnu
 dox powerpc64le powerpc64le-unknown-linux-gnu
 dox mips mips-unknown-linux-gnu
 dox mips64 mips64-unknown-linux-gnuabi64