drivers: net: xgene: fix kbuild warnings

Fixed the following kbuild warnings:
1. unused variable 'of_id'
2. buffer overflow 'ring_cfg' 5 <= 5
Signed-off-by: NIyappan Subramanian <isubramanian@apm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/apm/xgene/xgene_enet_main.c

@@ -1173,7 +1173,9 @@ static int xgene_enet_probe(struct platform_device *pdev)
 	struct xgene_enet_pdata *pdata;
 	struct device *dev = &pdev->dev;
 	struct xgene_mac_ops *mac_ops;
+#ifdef CONFIG_OF
 	const struct of_device_id *of_id;
+#endif
 	int ret;
 
 	ndev = alloc_etherdev(sizeof(struct xgene_enet_pdata));

drivers/net/ethernet/apm/xgene/xgene_enet_main.h

@@ -83,7 +83,7 @@ struct xgene_enet_desc_ring {
 	u16 irq;
 	char irq_name[IRQ_ID_SIZE];
 	u32 size;
-	u32 state[NUM_RING_CONFIG];
+	u32 state[X2_NUM_RING_CONFIG];
 	void __iomem *cmd_base;
 	void __iomem *cmd;
 	dma_addr_t dma;