xfrm: Use kmem_cache_zalloc() instead of kmem_cache_alloc() with flag GFP_ZERO.

Use kmem_cache_zalloc instead of manually setting kmem_cache_alloc
with flag GFP_ZERO since kzalloc sets allocated memory
to zero.

Change in v2:
     add indation
Signed-off-by: Huang Zijiang <huang.zijiang@zte.com.cn>
Signed-off-by: Yi Wang <wang.yi59@zte.com.cn>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/xfrm/xfrm_state.c

@@ -612,7 +612,7 @@ struct xfrm_state *xfrm_state_alloc(struct net *net)
 {
 	struct xfrm_state *x;
 
-	x = kmem_cache_alloc(xfrm_state_cache, GFP_ATOMIC | __GFP_ZERO);
+	x = kmem_cache_zalloc(xfrm_state_cache, GFP_ATOMIC);
 
 	if (x) {
 		write_pnet(&x->xs_net, net);