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/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index e23c779..582e832 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -1309,7 +1309,7 @@
 	/* process read if there is data other than line status */
 	if (tty && bytes > i) {
 		tty_insert_flip_string_fixed_flag(tty, data + i,
-				bytes - i, tty_flag);
+				tty_flag, bytes - i);
 		tty_flip_buffer_push(tty);
 	}