drivers: net: xgene: fix: Coalescing values for v2 hardware

Changing the interrupt trigger region id to 2 and the
corresponding threshold set0/set1 values to 8/16.

Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: Toan Le <toanle@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>