USB: cp210x: allow more baud rates above 1Mbaud

Allow more baud rates to be set in [1M,2M] baud.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Cc: Preston Fick <preston.fick@silabs.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/cp210x.c

@@ -394,10 +394,10 @@ static unsigned int cp210x_quantise_baudrate(unsigned int baud) {
 	else if (baud <= 491520)   baud = 460800;
 	else if (baud <= 567138)   baud = 500000;
 	else if (baud <= 670254)   baud = 576000;
-	else if (baud <= 1053257)  baud = 921600;
-	else if (baud <= 1474560)  baud = 1228800;
-	else if (baud <= 2457600)  baud = 1843200;
-	else                       baud = 3686400;
+	else if (baud < 1000000)
+		baud = 921600;
+	else if (baud > 2000000)
+		baud = 2000000;
 	return baud;
 }
 
@@ -615,7 +615,8 @@ static void cp210x_change_speed(struct tty_struct *tty,
 
 	baud = tty->termios->c_ospeed;
 
-	/* This maps the requested rate to a rate valid on cp2102 or cp2103.
+	/* This maps the requested rate to a rate valid on cp2102 or cp2103,
+	 * or to an arbitrary rate in [1M,2M].
 	 *
 	 * NOTE: B0 is not implemented.
 	 */