ARM: dts: qcom-msm8974-castor: Use &labels

Use &labels to align with the style used in new DTS and apply tiny
style fixes.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
[bjorn: Rebased ontop of Krzysztof's fixes]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220415115633.575010-14-konrad.dybcio@somainline.org