drm/msm/disp/dpu1/dpu_core_perf: Fix kernel-doc formatting issues

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c:31: warning: Enum value 'DPU_PERF_MODE_MAX' not described in enum 'dpu_perf_mode'
 drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c:34: warning: Cannot understand  * @_dpu_core_perf_calc_bw() - to calculate BW per crtc
 drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c:73: warning: Function parameter or member 'kms' not described in '_dpu_core_perf_calc_clk'
 drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c:73: warning: Function parameter or member 'crtc' not described in '_dpu_core_perf_calc_clk'
 drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c:73: warning: Function parameter or member 'state' not described in '_dpu_core_perf_calc_clk'
 drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c:249: warning: Cannot understand  * @dpu_core_perf_crtc_release_bw() - request zero bandwidth

Cc: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Kalyan Thota <kalyan_t@codeaurora.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: freedreno@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>