net/mlx5: minimize list critical sections

net/mlx5: minimize list critical sections

The mlx5 internal list utility is thread safe.

In order to synchronize list access between the threads, a RW lock is
taken for the critical sections.

The create\remove\clone\clone_free operations are in the critical
sections.

These operations are heavy and make the critical sections heavy because
they are used for memory and other resources allocations\deallocations.

Moved out the operations from the critical sections and use generation
counter in order to detect parallel allocations.

Signed-off-by: Matan Azrad <matan@nvidia.com>
Acked-by: Suanming Mou <suanmingm@nvidia.com>