[NETFILTER]: xt_iprange: fix sparse warnings

  CHECK   net/netfilter/xt_iprange.c
net/netfilter/xt_iprange.c:104:19: warning: restricted degrades to integer
net/netfilter/xt_iprange.c:104:37: warning: restricted degrades to integer
net/netfilter/xt_iprange.c:104:19: warning: restricted degrades to integer
net/netfilter/xt_iprange.c:104:37: warning: restricted degrades to integer
net/netfilter/xt_iprange.c:104:19: warning: restricted degrades to integer
net/netfilter/xt_iprange.c:104:37: warning: restricted degrades to integer
net/netfilter/xt_iprange.c:104:19: warning: restricted degrades to integer
net/netfilter/xt_iprange.c:104:37: warning: restricted degrades to integer

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>