drm/msm: Don't setup control node debugfs files

It's going away.

v2: Try harder to find them all.

Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Jordan Crouse <jcrouse@codeaurora.org>
Cc: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180503093107.25955-1-daniel.vetter@ffwll.ch