ARM: dts: vf-colibri-eval-v3.dts: Enable ST-M41T0M6 RTC

ST-M41T0M6 is available on Colibri carrier boards.
Hence enable M41T0M6 RTC.

Acked-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>