The regulator node 'regulator-3p3v-s0' was dupplicated. Remove it to
clean the DTS.

Fixes: 2a51f9da ("ARM: dts: imx6qdl-kontron-samx6i: Add iMX6-based Kontron SMARC-sAMX6i module")
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>