arm64: dts: qcom: Move sc7180 MI2S config to board files and make pulldown

arm64: dts: qcom: Move sc7180 MI2S config to board files and make pulldown

In general pinconf belongs in board files, not SoC files.  Move it to
the only current user (trogdor).  Also adjust the drive strengths and
pulls.

Cc: V Sujith Kumar Reddy <vsujithk@codeaurora.org>
Cc: Srinivasa Rao Mandadapu <srivasam@codeaurora.org>
Cc: Tzung-Bi Shih <tzungbi@chromium.org>
Cc: Judy Hsiao <judyhsiao@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20210301133318.v2.2.Id27e7e6f90c29bf623fa4880e18a14ba1dffd2d2@changeid
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>