tbb: use ppc32 for 32-bit ppc

This doesn't really matter as it only influences some cflags which
end up getting ignored for us, but whatever.

srcpkgs/tbb/template

@@ -31,7 +31,7 @@ case "$XBPS_TARGET_MACHINE" in
 		make_build_args="arch=ppc64"
 		;;
 	ppc*)
-		make_build_args="arch=ppc"
+		make_build_args="arch=ppc32"
 		;;
 	*)
 		# make sure to fall back instead of letting host uname control it