net: dpaa: Improve error reporting

net: dpaa: Improve error reporting

Instead of the generic error message emitted by the driver core when a
remove callback returns an error code ("remove callback returned a
non-zero value. This will be ignored."), emit a message describing the
actual problem and return zero to suppress the generic message.

Note that apart from suppressing the generic error message there are no
side effects by changing the return value to zero. This prepares
changing the remove callback to return void.

Acked-by: Madalin Bucur <madalin.bucur@oss.nxp.com>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230710071946.3470249-2-u.kleine-koenig@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>