clang: no need to depend on python3native/python3targetconfig

clang: no need to depend on python3native/python3targetconfig

Now that lldb has been split out of the clang recipe, there's no need
for the clang recipe to have Python integration beyond the current
Python major version for installing the libclang bindings, which can be
done by simply inheriting python3-dir.

The installation of six.py was done by lldb, and was removed in LLVM 16.

Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>