ksmbd: detect RDMA capable lower devices when bridge and vlan netdev is used

ksmbd: detect RDMA capable lower devices when bridge and vlan netdev is used

If user set bridge interface as actual RDMA-capable NICs are lower devices,
ksmbd can not detect as RDMA capable. This patch can detect the RDMA
capable lower devices from bridge master or VLAN. With this change, ksmbd
can accept both TCP and RDMA connections through the same bridge IP
address, allowing mixed transport operation without requiring separate
interfaces.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>