ARM: dts: imx/vf: Correct license text

The license text has been mangled at some point then copy pasted across
multiple files. Restore it to what it should be.
Note that this is not intended as a license change.

Reviewed-by: Heiko Schocher <hs@denx.de>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Afzal Mohammed <afzal.mohd.ma@gmail.com>
Acked-by: Michael Trimarchi <michael@amarulasolutions.com>
Acked-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>