ARM: dts: qcom: sdx65: correct SPMI node name

Node names should not have vendor prefixes:

  qcom-sdx65-mtp.dtb: qcom,spmi@c440000: $nodename:0: 'qcom,spmi@c440000' does not match '^spmi@.*

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20230924183103.49487-3-krzysztof.kozlowski@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>