arm64: dts: qcom: sc7180: Include gpio.h in edp bridge dts

The edp bridge dts fragment files use the macros defined in
'dt-bindings/gpio/gpio.h'.

To help us more flexibly order the #include lines of dts files in a
board-revision-specific dts file, let's include the gpio header in the
bridge dts fragment files themselves.

Signed-off-by: Philip Chen <philipchen@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211029152647.v3.1.Ie17e51ad3eb91d72826ce651ca2786534a360210@changeid