arm64: dts: qcom: msm8916: drop unused board-specific nodes

These nodes reserve and configure some pins as GPIOs. They are not
generic pinctrls, they actually belong to board files but they are not
used by any other node, so just drop them altogether.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>