dt-bindings: arm: fsl: Add MYiR Tech boards

Add entries for MYiR Tech imx6ULL eval boards.

Signed-off-by: Parthiban Nallathambi <parthiban@linumiz.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>