driver core: class: remove boilerplate code

Jump to err_out to avoid duplicating the code.

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Link: https://lore.kernel.org/r/20231020160042.759439-1-mlombard@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>