drm/msm: add another DRM_DISPLAY_DSC_HELPER selection

drm/msm: add another DRM_DISPLAY_DSC_HELPER selection

In the drm/msm driver both DSI and DPU subdrivers use drm_dsc_*
functions, but only DSI selects DRM_DISPLAY_DSC_HELPER symbol. Add
missing select to the DPU subdriver too.

Fixes: ca097d4d94d8 ("drm/display: split DSC helpers from DP helpers")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202409040129.rqhtRTeC-lkp@intel.com/
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240905-fix-dsc-helpers-v1-2-3ae4b5900f89@linaro.org
Signed-off-by: Maxime Ripard <mripard@kernel.org>