arm64: dts: qcom: sc8280xp: correct GIC child node name

GIC child node is supposed to be named msi-controller:

  sa8295p-adp.dtb: interrupt-controller@17a00000: gic-its@17a40000: False schema does not allow

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230417080939.28648-3-krzysztof.kozlowski@linaro.org