arm64: dts: qcom: ipq6018: Update WCSS PIL driver compatible

Updated WCSS PIL driver node with IPQ6018 specific
compatible to enable SoC specific driver data.

Signed-off-by: Gokul Sriram Palanisamy <gokulsri@codeaurora.org>
Link: https://lore.kernel.org/r/1611940320-24830-4-git-send-email-gokulsri@codeaurora.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>