[ICMP]: Restore pskb_pull calls in receive function

Somewhere along the development of my ICMP relookup patch the header
length check went AWOL on the non-IPsec path.  This patch restores the
check.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index a7321a8..a13c074 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -1015,7 +1015,8 @@
 			goto error;
 	}
 
-	__skb_pull(skb, sizeof(*icmph));
+	if (!pskb_pull(skb, sizeof(*icmph)))
+		goto error;
 
 	icmph = icmp_hdr(skb);