tty: serial: rda: Fix the link time qualifier of 'rda_uart_exit()'

'exit' functions should be marked as __exit, not __init.

Fixes: c10b1332 ("tty: serial: Add RDA8810PL UART driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/20190910041702.7357-1-christophe.jaillet@wanadoo.frSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/rda-uart.c

@@ -815,7 +815,7 @@ static int __init rda_uart_init(void)
 	return ret;
 }
 
-static void __init rda_uart_exit(void)
+static void __exit rda_uart_exit(void)
 {
 	platform_driver_unregister(&rda_uart_platform_driver);
 	uart_unregister_driver(&rda_uart_driver);