stmmac: remove BUS_MODE_DA

This is a very old and often unused option to configure
a bit in a register inside the DMA. This support should
not stay under Koption and should be extended for new chips too.
This will be do later maybe via device-tree parameters.
Also no performance impact when remove this setting on STi platforms.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -37,14 +37,4 @@ config STMMAC_PCI
 	  D1215994A VIRTEX FPGA board.
 
 	  If unsure, say N.
-
-config STMMAC_DA
-	bool "STMMAC DMA arbitration scheme"
-	default n
-	---help---
-	  Selecting this option, rx has priority over Tx (only for Giga
-	  Ethernet device).
-	  By default, the DMA arbitration scheme is based on Round-robin
-	  (rx:tx priority is 1:1).
-
 endif

drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c

@@ -70,10 +70,6 @@ static int dwmac1000_dma_init(void __iomem *ioaddr, int pbl, int fb, int mb,
 	if (mb)
 		value |= DMA_BUS_MODE_MB;
 
-#ifdef CONFIG_STMMAC_DA
-	value |= DMA_BUS_MODE_DA;	/* Rx has priority over tx */
-#endif
-
 	if (atds)
 		value |= DMA_BUS_MODE_ATDS;