ARM: dts: socfpga: Change Mercury+ AA1 dts to dtsi

The Mercury+ AA1 is not a standalone board, rather it's a module
with an Arria 10 SoC. Remove status = "okay" and i2c aliases, as they
are routed to the base board and should be enabled from there.

Signed-off-by: Paweł Anikiel <pan@semihalf.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>