arm64: dts: qcom: sc8280xp-x13s: add wifi calibration variant

Describe the bus topology for PCIe domain 6 and add the ath11k
calibration variant so that the board file (calibration data) can be
loaded.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216246


Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Tested-by: Steev Klimaszewski <steev@kali.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230321094011.9759-3-johan+linaro@kernel.org