net: cxgb3: Fix an error code when probing the driver

During the process of driver probing, probe function should return < 0
for failure, otherwise kernel will treat value >= 0 as success.

Therefore, the driver should set 'err' to -ENODEV when
'adapter->registered_device_map' is NULL. Otherwise kernel will assume
that the driver has been successfully probed and will cause unexpected
errors.

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/1646546192-32737-1-git-send-email-zheyuma97@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>