amd-xgbe: Rename MAX_DMA_CHANNELS to avoid powerpc conflict

MAX_DMA_CHANNELS is defined in asm/scatterlist.h of the powerpc
architecture.  Rename this #define in xgbe.h to avoid the
redefined warning issued during compilation.
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/amd/xgbe/xgbe-main.c

@@ -230,7 +230,7 @@ static int xgbe_probe(struct platform_device *pdev)
 	DBGPR("--> xgbe_probe\n");
 
 	netdev = alloc_etherdev_mq(sizeof(struct xgbe_prv_data),
-				   MAX_DMA_CHANNELS);
+				   XGBE_MAX_DMA_CHANNELS);
 	if (!netdev) {
 		dev_err(dev, "alloc_etherdev failed\n");
 		ret = -ENOMEM;

drivers/net/ethernet/amd/xgbe/xgbe.h

@@ -138,7 +138,7 @@
 #define RX_MIN_BUF_SIZE		(ETH_FRAME_LEN + ETH_FCS_LEN + VLAN_HLEN)
 #define RX_BUF_ALIGN		64
 
-#define MAX_DMA_CHANNELS	16
+#define XGBE_MAX_DMA_CHANNELS	16
 #define DMA_ARDOMAIN_SETTING	0x2
 #define DMA_ARCACHE_SETTING	0xb
 #define DMA_AWDOMAIN_SETTING	0x2