ARM: dts: qcom: msm8974-klte: Add gpio-keys nodes

This introduces the gpio-keys nodes for volume/home keys and the
associated pinctrl state.

Signed-off-by: Daniele Debernardi <drebrez@gmail.com>
Link: https://lore.kernel.org/r/20200411182122.2677248-4-iskren.chernev@gmail.com


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>