xfrm: use correct size to initialise sp->ovec

This place should want to initialize array, not a element,
so it should be sizeof(array) instead of sizeof(element)

but now this array only has one element, so no error in
this condition that XFRM_MAX_OFFLOAD_DEPTH is 1

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/xfrm/xfrm_input.c

@@ -131,7 +131,7 @@ struct sec_path *secpath_dup(struct sec_path *src)
 	sp->len = 0;
 	sp->olen = 0;
 
-	memset(sp->ovec, 0, sizeof(sp->ovec[XFRM_MAX_OFFLOAD_DEPTH]));
+	memset(sp->ovec, 0, sizeof(sp->ovec));
 
 	if (src) {
 		int i;