bitrate: fix calculation to match API description

[ upstream commit bdd478e ]

rte_stats_bitrate_calc() API states it returns 'Negative value on error'.

However, the implementation will return the error code from
rte_eth_stats_get() which may be non-zero on error.

Change the implementation of rte_stats_bitrate_calc() to match
the API description by always returning a negative value on error.

Fixes: 2ad7ba9 ("bitrate: add bitrate statistics library")

Signed-off-by: Kevin Traynor <ktraynor@redhat.com>

lib/librte_bitratestats/rte_bitrate.c

@@ -74,7 +74,7 @@ rte_stats_bitrate_calc(struct rte_stats_bitrates *bitrate_data,
 
 	ret_code = rte_eth_stats_get(port_id, &eth_stats);
 	if (ret_code != 0)
-		return ret_code;
+		return ret_code < 0 ? ret_code : -ret_code;
 
 	port_data = &bitrate_data->port_stats[port_id];