serial: xuartps: Fix cdns_uart_port[] definition.

The code assumes that the array cdns_uart_port[] has dimension
CDNS_UART_NR_PORTS, so let us define it this way.
Signed-off-by: NThomas Betker <thomas.betker@rohde-schwarz.com>
Reviewed-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/xilinx_uartps.c

@@ -1010,7 +1010,7 @@ static struct uart_ops cdns_uart_ops = {
 #endif
 };
 
-static struct uart_port cdns_uart_port[2];
+static struct uart_port cdns_uart_port[CDNS_UART_NR_PORTS];
 
 /**
  * cdns_uart_get_port - Configure the port from platform device resource info