net: hso: add failure handler for add_net_device

If the network devices connected to the system beyond
HSO_MAX_NET_DEVICES. add_net_device() in hso_create_net_device()
will be failed for the network_table is full. It will lead to
business failure which rely on network_table, for example,
hso_suspend() and hso_resume(). It will also lead to memory leak
because resource release process can not search the hso_device
object from network_table in hso_free_interface().

Add failure handler for add_net_device() in hso_create_net_device()
to solve the above problems.

Fixes: 72dc1c09 ("HSO: add option hso driver")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>