driver core: faux: only create the device if probe() succeeds

driver core: faux: only create the device if probe() succeeds

It's really hard to know if a faux device properly passes the callback
to probe() without having to poke around in the faux_device structure
and then clean up.  Instead of having to have every user of the api do
this logic, just do it in the faux device core itself.

This makes the use of a custom probe() callback for a faux device much
simpler overall.

Suggested-by: Kurt Borja <kuurtb@gmail.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Kurt Borja <kuurtb@gmail.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/2025022545-unroasted-common-fa0e@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>