ARM: dts: qcom: apq8074-dragonboard: add gpio keys

Add device nodes for gpio-keys (volume-up, general key) device nodes.

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230531012627.3813060-3-dmitry.baryshkov@linaro.org