drm/msm/dpu: Remove bogus comment

This comment doesn't make any sense, remove it.

Suggested-by: Jordan Crouse <jcrouse@codeaurora.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528182657.246714-1-sean@poorly.run