arm64: dts: qcom: ipq6018: add label to remoteproc node

glink-edge bindings require label:

  ipq6018-cp01-c1.dtb: glink-edge: 'label' is a required property

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220517070113.18023-10-krzysztof.kozlowski@linaro.org