ARM: dts: imx7s-warp: Add initial support

Add the initial support for the Warp7 board.

For more information about this reference design, please visit:

https://www.element14.com/community/docs/DOC-79058/l/warp-7-the-next-generation-wearable-reference-platform



Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>