gro: fix identifying fragmented packets

gro: fix identifying fragmented packets

A packet with RTE_PTYPE_L4_FRAG(0x300) contains both RTE_PTYPE_L4_TCP
(0x100) & RTE_PTYPE_L4_UDP (0x200). A fragmented packet as defined in
rte_mbuf_ptype.h cannot be recognized as other L4 types and hence the
GRO layer should not use IS_IPV4_TCP_PKT or IS_IPV4_UDP_PKT for
RTE_PTYPE_L4_FRAG. Hence, if the packet type is RTE_PTYPE_L4_FRAG the
IP header should be parsed to recognize the appropriate IP type and
invoke the respective gro handler.

Fixes: 1ca5e6740852 ("gro: support UDP/IPv4")
Cc: stable@dpdk.org
Signed-off-by: Kumara Parameshwaran <kumaraparamesh92@gmail.com>
Reviewed-by: Jiayu Hu <jiayu.hu@intel.com>