net: aquantia: Bad udp rate on default interrupt coalescing

Default Tx rates cause very long ISR delays on Tx.
0xff is 510us delay, giving only ~ 2000 interrupts per seconds for
Tx rings cleanup. With these settings udp tx rate was never higher than
~800Mbps on a single stream. Changing min delay to 0xF makes it
way better with ~6Gbps

TCP stream performance is almost unaffected by this change, since LSO
optimizations play important role.

CPU load is affected insignificantly by this change.

Signed-off-by: Pavel Belous <pavel.belous@aquantia.com>
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c

@@ -821,12 +821,12 @@ static int hw_atl_b0_hw_interrupt_moderation_set(struct aq_hw_s *self)
 			itr_rx |= rx_max_timer << 0x10U;
 		} else {
 			static unsigned int hw_atl_b0_timers_table_tx_[][2] = {
-				{0xffU, 0xffU}, /* 10Gbit */
-				{0xffU, 0x1ffU}, /* 5Gbit */
-				{0xffU, 0x1ffU}, /* 5Gbit 5GS */
-				{0xffU, 0x1ffU}, /* 2.5Gbit */
-				{0xffU, 0x1ffU}, /* 1Gbit */
-				{0xffU, 0x1ffU}, /* 100Mbit */
+				{0xfU, 0xffU}, /* 10Gbit */
+				{0xfU, 0x1ffU}, /* 5Gbit */
+				{0xfU, 0x1ffU}, /* 5Gbit 5GS */
+				{0xfU, 0x1ffU}, /* 2.5Gbit */
+				{0xfU, 0x1ffU}, /* 1Gbit */
+				{0xfU, 0x1ffU}, /* 100Mbit */
 			};
 
 			static unsigned int hw_atl_b0_timers_table_rx_[][2] = {