RDMA/counter: Check CAP_NET_RAW check in user namespace for RDMA counters

RDMA/counter: Check CAP_NET_RAW check in user namespace for RDMA counters

Currently, the capability check is done in the default
init_user_ns user namespace. When a process runs in a
non default user namespace, such check fails.

Since the RDMA device is a resource within a network namespace,
use the network namespace associated with the RDMA device to
determine its owning user namespace.

Fixes: 1bd8e0a9d0fd ("RDMA/counter: Allow manual mode configuration support")
Signed-off-by: Parav Pandit <parav@nvidia.com>
Link: https://patch.msgid.link/68e2064e72e94558a576fdbbb987681a64f6fea8.1750963874.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>