net: mvneta: Prevent out of bounds read in mvneta_config_rss()

The pp->indir[0] value comes from the user.  It is passed to:

	if (cpu_online(pp->rxq_def))

inside the mvneta_percpu_elect() function.  It needs bounds checkeding
to ensure that it is not beyond the end of the cpu bitmap.

Fixes: cad5d84 ("net: mvneta: Fix the CPU choice in mvneta_percpu_elect")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvneta.c

@@ -4927,6 +4927,9 @@ static int  mvneta_config_rss(struct mvneta_port *pp)
 		napi_disable(&pp->napi);
 	}
 
+	if (pp->indir[0] >= nr_cpu_ids)
+		return -EINVAL;
+
 	pp->rxq_def = pp->indir[0];
 
 	/* Update unicast mapping */