mlx4: Use snprintf instead of complicated strcpy

This fixes a compilation warning in sysfs.c

drivers/infiniband/hw/mlx4/sysfs.c:360:2: warning: 'strncpy' output may be
truncated copying 8 bytes from a string of length 31
[-Wstringop-truncation]

By eliminating the temporary stack buffer.
Signed-off-by: Qian Cai <cai@gmx.us>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/mlx4/sysfs.c

@@ -353,16 +353,12 @@ static int add_port_entries(struct mlx4_ib_dev *device, int port_num)
 
 static void get_name(struct mlx4_ib_dev *dev, char *name, int i, int max)
 {
-	char base_name[9];
-
-	/* pci_name format is: bus:dev:func -> xxxx:yy:zz.n */
-	strlcpy(name, pci_name(dev->dev->persist->pdev), max);
-	strncpy(base_name, name, 8); /*till xxxx:yy:*/
-	base_name[8] = '\0';
-	/* with no ARI only 3 last bits are used so when the fn is higher than 8
+	/* pci_name format is: bus:dev:func -> xxxx:yy:zz.n
+	 * with no ARI only 3 last bits are used so when the fn is higher than 8
 	 * need to add it to the dev num, so count in the last number will be
 	 * modulo 8 */
-	sprintf(name, "%s%.2d.%d", base_name, (i/8), (i%8));
+	snprintf(name, max, "%.8s%.2d.%d", pci_name(dev->dev->persist->pdev),
+		 i / 8, i % 8);
 }
 
 struct mlx4_port {