Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: be51da0f ("ieee802154: Stop using NLA_PUT*().")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NZhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210508062517.2574-1-thunder.leizhen@huawei.comSigned-off-by: NStefan Schmidt <stefan@datenfreihafen.org>