drm/msm/dpu: fix kernel-doc warnings

Correct all kernel-doc warnings in dpu_encoder.c and dpu_rm.c:

dpu_encoder.c:212: warning: Excess struct member 'crtc_kickoff_cb' description in 'dpu_encoder_virt'
dpu_encoder.c:212: warning: Excess struct member 'crtc_kickoff_cb_data' description in 'dpu_encoder_virt'
dpu_encoder.c:212: warning: Excess struct member 'debugfs_root' description in 'dpu_encoder_virt'

dpu_rm.c:35: warning: Excess struct member 'hw_res' description in 'dpu_rm_requirements'
dpu_rm.c:208: warning: No description found for return value of '_dpu_rm_get_lm_peer'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Sean Paul <sean@poorly.run>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: freedreno@lists.freedesktop.org
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Paloma Arellano <quic_parellan@quicinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312170641.5exlvQQx-lkp@intel.com/
Fixes: 62d35629 ("drm/msm/dpu: move encoder status to standard encoder debugfs dir")
Fixes: 25fdd593

 ("drm/msm: Add SDM845 DPU support")
Patchwork: https://patchwork.freedesktop.org/patch/572962/
Link: https://lore.kernel.org/r/20231231060823.1934-1-rdunlap@infradead.org
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>