USB: serial: pl2303 works at 500kbps

My PL2303HX works at 500kbps after applying this patch.
I suppose that it could work at other non standard speeds since this fix

"correctly handle baudrates above 115200"
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/usb/serial/pl2303.c?id=8d48fdf689fed2c73c493e5146d1463689246442

came after this one

"fix baud rate handling in case of unsupported values"
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/usb/serial/pl2303.c?id=25b8286805e856c8c7fda127018e31032c918015

but I only can test it with 500000.
Patch made against mainline but tested with 3.4.45

Signed-off-by: Luca Olivetti <luca@ventoso.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/serial/pl2303.c

@@ -275,7 +275,7 @@ static void pl2303_set_termios(struct tty_struct *tty,
 	u8 control;
 	const int baud_sup[] = { 75, 150, 300, 600, 1200, 1800, 2400, 3600,
 	                         4800, 7200, 9600, 14400, 19200, 28800, 38400,
-	                         57600, 115200, 230400, 460800, 614400,
+	                         57600, 115200, 230400, 460800, 500000, 614400,
 	                         921600, 1228800, 2457600, 3000000, 6000000 };
 	int baud_floor, baud_ceil;
 	int k;