ring: fix error code when creating ring

[ upstream commit 074717be3ef9e7a8868b5af078b0ca7b61bcc44b ]

The error value returned by rte_ring_create_elem() should be positive
integers. However, if the rte_ring_get_memsize_elem() function fails,
a negative number is returned and is directly used as the return value.
As a result, this will cause the external call to check the return
value to fail(like called by rte_mempool_create()).

Fixes: a182620 ("ring: get size in memory")

Reported-by: Nan Zhou <zhounan14@huawei.com>
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

lib/librte_ring/rte_ring.c

@@ -137,7 +137,7 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
 
 	ring_size = rte_ring_get_memsize(count);
 	if (ring_size < 0) {
-		rte_errno = ring_size;
+		rte_errno = -ring_size;
 		return NULL;
 	}