amd-xgbe: Remove Tx coalescing

The Tx coalescing support in the driver was a software implementation
for something lacking in the hardware. Using hrtimers, the idea was to
trigger a timer interrupt after having queued a packet for transmit.
Unfortunately, as the timer value was lowered, the timer expired before
the hardware actually did the transmit and so it was racey and resulted
in unnecessary interrupts.

Remove the Tx coalescing support and hrtimer and replace with a Tx timer
that is used as a reclaim timer in case of inactivity.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe.h b/drivers/net/ethernet/amd/xgbe/xgbe.h
index bfe11fb..72b8f27 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe.h
+++ b/drivers/net/ethernet/amd/xgbe/xgbe.h
@@ -222,7 +222,7 @@
 	 ((_idx) & ((_ring)->rdesc_count - 1)))
 
 /* Default coalescing parameters */
-#define XGMAC_INIT_DMA_TX_USECS		50
+#define XGMAC_INIT_DMA_TX_USECS		1000
 #define XGMAC_INIT_DMA_TX_FRAMES	25
 
 #define XGMAC_MAX_DMA_RIWT		0xff
@@ -410,7 +410,7 @@
 	unsigned int saved_ier;
 
 	unsigned int tx_timer_active;
-	struct hrtimer tx_timer;
+	struct timer_list tx_timer;
 
 	struct xgbe_ring *tx_ring;
 	struct xgbe_ring *rx_ring;