ah4/ah6: remove useless NULL assignments

struct will be kfreed in a moment, so...
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ah4.c

@@ -293,9 +293,7 @@ static void ah_destroy(struct xfrm_state *x)
 		return;
 
 	kfree(ahp->work_icv);
-	ahp->work_icv = NULL;
 	crypto_free_hash(ahp->tfm);
-	ahp->tfm = NULL;
 	kfree(ahp);
 }
 

net/ipv6/ah6.c

@@ -509,9 +509,7 @@ static void ah6_destroy(struct xfrm_state *x)
 		return;
 
 	kfree(ahp->work_icv);
-	ahp->work_icv = NULL;
 	crypto_free_hash(ahp->tfm);
-	ahp->tfm = NULL;
 	kfree(ahp);
 }