arm64: dts: Add Airoha EN7581 SoC and EN7581 Evaluation Board

arm64: dts: Add Airoha EN7581 SoC and EN7581 Evaluation Board

Introduce the Airoha EN7581 SoC's dtsi and the Airoha EN7581 Evaluation
Board's dts file, as well as the required Makefiles.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Daniel Danzberger <dd@embedd.com>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/f05a36dd7e8ef34ead8a63aa10fcffb542229404.1709975956.git.lorenzo@kernel.org
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>