ARM: dts: imx6qdl-vicut1.dtsi: add thermal zone and attach tmp103 to it.

Latest version of ti,tmp103 driver supports thermal zone. So make use of
it.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>