arm64: dts: qcom: bullhead: Move UART pinctrl to SoC

This pinout is common for every 8992-based device and
should therefore reside in the SoC device tree.

Also convert addresses into phandles.

Signed-off-by: Konrad Dybcio <konradybcio@gmail.com>
Link: https://lore.kernel.org/r/20200625182118.131476-5-konradybcio@gmail.com


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>