dt-bindings: arm: qcom: Document samsung,milletwifi device

Add binding documentation for Samsung Galaxy Tab 4 8.0 Wi-Fi
tablet which is based on Snapdragon 400 (apq8026) SoC.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Bryant Mairs <bryant@mai.rs>
Link: https://lore.kernel.org/r/20240219214643.197116-2-bryant@mai.rs


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