usb/serial/io_ti.c: inconsequent NULL checking

[Adrian Bunk <bunk@kernel.org>]

The Coverity checker spotted the following inconsequent NULL checking 
introduced by commit d5f5bcd425b771c0b7ff5a650b2ce061ac8bbb87:

<--  snip  -->

static int edge_open (struct usb_serial_port *port, struct file * filp)
{
...
        if (port->tty)   <---------------------------------------------
                port->tty->low_latency = low_latency;

        port_number = port->number - port->serial->minor;
        switch (port_number) {
                case 0:
                        edge_port->uart_base = UMPMEM_BASE_UART1;
                        edge_port->dma_address = UMPD_OEDB1_ADDRESS;
                        break;
                case 1:
                        edge_port->uart_base = UMPMEM_BASE_UART2;
                        edge_port->dma_address = UMPD_OEDB2_ADDRESS;
                        break;
                default:
                        dev_err (&port->dev, "Unknown port number!!!\n");
                        return -ENODEV;
        }

        dbg ("%s - port_number = %d, uart_base = %04x, dma_address = %04x",
             __FUNCTION__, port_number, edge_port->uart_base, edge_port->dma_address);

        dev = port->serial->dev;

        memset (&(edge_port->icount), 0x00, sizeof(edge_port->icount));
        init_waitqueue_head (&edge_port->delta_msr_wait);

        /* turn off loopback */
        status = TIClearLoopBack (edge_port);
        if (status) {
                dev_err(&port->dev,"%s - cannot send clear loopback command, %d\n",
                        __FUNCTION__, status);
                return status;
        }
        
        /* set up the port settings */
        edge_set_termios (port, port->tty->termios);
...                             ^^^^^^^^^^^^^^^^^^

<--  snip  -->

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed