net/i40e: fix parsing packet type for NEON

net/i40e: fix parsing packet type for NEON

In i40e NEON vector Rx path, the packet descs processing is incorrect.
This caused wrong packet type been filled in mbuf.

To fix this, when shifting the pktlen field to be 16-bit aligned, it
only needs to process the high 16bit of the packet descs instead of
the high 32bit.

Test Results:
Architecture: arm64
NIC: XL710
Driver: i40e
Package: Ether()/IP()/

Without this patch:
desc_to_ptype_v: ptype = 7 (error)

With this patch:
desc_to_ptype_v: ptype = 23 (correct)

Fixes: ae0eb310f253 ("net/i40e: implement vector PMD for ARM")
Cc: stable@dpdk.org
Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Tested-by: Kathleen Capella <kathleen.capella@arm.com>