ip_frag: fix overflow in key comparison
ip_frag: fix overflow in key comparison

in struct ip_frag_key,src_dst[] type is uint64_t.
but "val" which to store the calc restult ,type is uint32_t.
we may lost high 32 bit key. and function return value is int,
but it won't return < 0.

Signed-off-by: Li Han <00ea541693ff2cae2a6da220ad54499f8e259e9c@zte.com.cn>
Acked-by: Konstantin Ananyev <cbd5212b59ab42a210d72992d23a3aa17cfd3eaf@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk