drm/msm/dpu: fix unitialized variable error

 drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c:817 dpu_crtc_enable() error: uninitialized symbol 'request_bandwidth'.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>