igb: set default thresholds based on MAC type

igb: set default thresholds based on MAC type

This brings the DPDK igb driver inline with the behavior used by
the current Linux driver. The IGB hardware has several different
MAC types and the threshold values that work vary based on the hardware.

Since DPDK 1.8 it has been up to devices to provide the correct default
configuration parameter. But the igb driver gives values that are broken
on some devices, and always causes a warning message at startup.

Please test this on real hardware, I don't have the luxury of a
hardware lab full of variations of this chip.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Wenzhuo Lu <wenzhuo.lu@intel.com>