ARM: dts: imx7s-warp: enable i2c3 device support

The WaRP7 has one mikroBUS socket on the back to plug click boards.
This patch allows to interact with some of these
i2c modules (EEPROM, RTC and so on).

Signed-off-by: Pierre-Jean Texier <texier.pj2@gmail.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>