netxen: Delete an unnecessary check before the function call "kfree"

The kfree() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/netxen/netxen_nic_main.c

@@ -176,9 +176,7 @@ netxen_alloc_sds_rings(struct netxen_recv_context *recv_ctx, int count)
 static void
 netxen_free_sds_rings(struct netxen_recv_context *recv_ctx)
 {
-	if (recv_ctx->sds_rings != NULL)
 	kfree(recv_ctx->sds_rings);
-
 	recv_ctx->sds_rings = NULL;
 }