xfrm: policy: silence sparse warning in xfrm_policy_unregister_afinfo

xfrm_policy_afinfo is __rcu, use rcu_access_pointer to silence:

net/xfrm/xfrm_policy.c:4152:43: error: incompatible types in comparison expression (different address spaces):
net/xfrm/xfrm_policy.c:4152:43:    struct xfrm_policy_afinfo const [noderef] __rcu *
net/xfrm/xfrm_policy.c:4152:43:    struct xfrm_policy_afinfo const *

Signed-off-by: Sabrina Dubroca <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Signed-off-by: Steffen Klassert <[email protected]>

Author: qsn

net/xfrm/xfrm_policy.c

@@ -4156,7 +4156,7 @@ void xfrm_policy_unregister_afinfo(const struct xfrm_policy_afinfo *afinfo)
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(xfrm_policy_afinfo); i++) {
-		if (xfrm_policy_afinfo[i] != afinfo)
+		if (rcu_access_pointer(xfrm_policy_afinfo[i]) != afinfo)
 			continue;
 		RCU_INIT_POINTER(xfrm_policy_afinfo[i], NULL);
 		break;