dockerfiles: install bindgen from cargo on Ubuntu 22.04

dockerfiles: install bindgen from cargo on Ubuntu 22.04

Because Ubuntu 22.04 has a very old version of bindgen, that
does not have the important option --allowlist-file, it will
not be able to use --enable-rust out of the box.  Instead,
install the latest version of bindgen-cli via "cargo install"
in the container, following QEMU's own documentation.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>