net/octeontx_ep: fix null pointer access

mz is known to be NULL. Do not use it to print a memzone name.

Fixes: 242e18c056 ("net/octeontx_ep: add Rx queue setup and release")
Cc: stable@dpdk.org

Signed-off-by: Thierry Herbelot <thierry.herbelot@6wind.com>

drivers/net/octeontx_ep/otx_ep_rxtx.c

@@ -27,7 +27,7 @@ otx_ep_dmazone_free(const struct rte_memzone *mz)
 	int ret = 0;
 
 	if (mz == NULL) {
-		otx_ep_err("Memzone %s : NULL\n", mz->name);
+		otx_ep_err("Memzone: NULL\n");
 		return;
 	}