arm64: dts: intel: socfpga_agilex: align node names with dtschema

Align the NAND, GIC and UART node names with dtschema to silence
dtbs_check warnings like:

    arch/arm64/boot/dts/intel/socfpga_agilex_socdk.dt.yaml:
        intc@fffc1000: $nodename:0: 'intc@fffc1000' does not match '^interrupt-controller(@[0-9a-f,]+)*$'
    arch/arm64/boot/dts/intel/socfpga_agilex_socdk.dt.yaml:
        serial0@ffc02000: $nodename:0: 'serial0@ffc02000' does not match '^serial(@[0-9a-f,]+)*$'

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>