arm64: dts: qcom: msm/apq8x96-*: Fix up comments

Switch '//' comments to C-style /* */ and fix up the contents of some.
Make sure all multiline C-style commends begin with just '/*' with
the comment text starting on a new line.
Also, fix up a single raw '2' to PM8994_GPIO_S4 while at it.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221107145522.6706-3-konrad.dybcio@linaro.org