ixl: Increase tx/rx ring size to 8160

I've verified the tx queue (table 8-22) in addition.

DPDK commit message

net/i40e: increase max descriptor queue length
According to the Intel X710/XXV710/XL710 Datasheet, the maximum receive
queue descriptor length is 0x1FE0 (8160 in base 10). This is specified
as QLEN in table 8-12, page 1083.

I've tested this change with an XXV710 NIC and it has positive effect on
performance under high load scenarios. Where previously I'd get
~2000 packets/sec miss rate, now I get only ~40 packets/sec miss rate.

Signed-off-by: Igor Gutorov <igootorov@gmail.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

Obtained from: DPDK (ce9470f)
MFC after: 1 week