arm64: dts: qcom: sm8150-kumano: Add GPIO keys

Configure hardware buttons (V-, Camera Shutter/Focus) on Kumano
devices.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Tested-by: Marijn Suijten <marijn.suijten@somainline.org> # On Xperia 1 and Xperia 5
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221210142525.16974-1-konrad.dybcio@linaro.org