drm/msm/dpu: Remove duplicate header

Remove dpu_kms.h which is included more than once

Signed-off-by: Sabyasachi Gupta <sabyasachi.linux@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/5cda6de6.1c69fb81.a3ae5.836a@mx.google.com