arm64: dts: qcom: sm6350-lena: Include pm6350 and configure buttons

Include pm6350 to inherit its GPIO and button configuration, and
configure "resin" to serve as volume up, and gpio2 as volume down.

Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221030073232.22726-6-marijn.suijten@somainline.org