Add DT compatible string for RVE gateway board based on a Variscite
VAR-SOM-NANO with a NXP MX8MN nano CPU.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>