USB: tty: fix incorrect use of tty_insert_flip_string_fixed_flag

Fix regression introduced by commit
a108bfcb372d8c4452701039308fb95747911c59 (USB: tty: Prune uses of
tty_request_room in the USB layer) which broke three drivers
(cypress_m8, digi_acceleport and spcp8x5) through incorrect use of
tty_insert_flip_string_fixed_flag.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Cc: stable <stable@kernel.org>  [.34]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/spcp8x5.c b/drivers/usb/serial/spcp8x5.c
index 5d39191..2ea32c5 100644
--- a/drivers/usb/serial/spcp8x5.c
+++ b/drivers/usb/serial/spcp8x5.c
@@ -726,8 +726,8 @@
 		/* overrun is special, not associated with a char */
 		if (status & UART_OVERRUN_ERROR)
 			tty_insert_flip_char(tty, 0, TTY_OVERRUN);
-		tty_insert_flip_string_fixed_flag(tty, data,
-						urb->actual_length, tty_flag);
+		tty_insert_flip_string_fixed_flag(tty, data, tty_flag,
+							urb->actual_length);
 		tty_flip_buffer_push(tty);
 	}
 	tty_kref_put(tty);