test/ring: do not mask result of enqueue or dequeue

test/ring: do not mask result of enqueue or dequeue

The define RTE_RING_SZ_MASK is the maximum size supported by the
rte_ring. The size is checked at ring creation.

There is no reason today to mask the result of
rte_ring_sp_enqueue_burst() or rte_ring_sc_dequeue_burst() with this
value. The flag RTE_RING_QUOT_EXCEED was previously included in the
returned value but it was removed in
commit 77dd3064270c ("ring: remove watermark support").

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>