serial: 8250: Simplify capabilities reset at port unregister

Since uart->port.type has just reset to PORT_UNKNOWN, capabilities
are reset to uart_config[PORT_UNKNOWN].flags, which is 0.

Removes unnecessary dependency on uart_config[].
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_core.c

@@ -3747,7 +3747,7 @@ void serial8250_unregister_port(int line)
 		uart->port.flags &= ~UPF_BOOT_AUTOCONF;
 		uart->port.type = PORT_UNKNOWN;
 		uart->port.dev = &serial8250_isa_devs->dev;
-		uart->capabilities = uart_config[uart->port.type].flags;
+		uart->capabilities = 0;
 		uart_add_one_port(&serial8250_reg, &uart->port);
 	} else {
 		uart->port.dev = NULL;