net-sysfs: remove unused initial ret values

In some net-sysfs functions the ret value is initialized but never used
as it is always overridden. Remove those.

Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Link: https://patch.msgid.link/20250226174644.311136-1-atenart@kernel.org


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