net/mlx5e: Non-atomic indicator for ring enabled state

Rings enabled state change occurs in control path only, and is always
followed by a napi_sychronize(), so that following NAPIs read the
new value. This read does not need to be atomic.

The RQ auto-moderation bit is not set/cleared in data-path.
No need for atomic read, a regular read operation is sufficient.
In RQ creation time as well, there's no multiple threads trying
to access it yet, hence a regular read can be used.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>