arm64: dts: qcom: msm8998-xperia: Add support for wcn3990 Bluetooth

This platform uses the WCN3990 Bluetooth chip, reachable on UART-3.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210909123733.367248-3-angelogioacchino.delregno@somainline.org