ring_queue: kernel style change, replace uint32_t with u32

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
ring_queue: cleanup ring_queue.c a bit

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
ring_queue: correct use of memory barriers

Correct the use of memory barries to use the kernel versions, which
should also (hopefully)  be more correct for weak Memory Ordering archs.

Keeping the compiler barrier() from DPDK for now.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
ring_queue: more memory barriers, perhaps needed

Removing the compiler barriers with some real memory barries.
For Intel archs this will still be a compiler barrier.

I'm more uncertain if these memory barries are really needed.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>