net/enic: refill only the address of the RQ descriptor
net/enic: refill only the address of the RQ descriptor

Once the RQ descriptors are initialized (enic_alloc_rx_queue_mbufs),
their length_type does not change during normal RX
operations. rx_pkt_burst only needs to reset their address field for
newly allocated mbufs.

Signed-off-by: Hyong Youb Kim <410cadac1eb3154f1b3752aedc2559ad69f3863e@cisco.com>
Reviewed-by: John Daley <097981eb5abe5dbeac3142a4f5a88742d916de86@cisco.com>

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