drm/msm/disp/dpu1/dpu_hw_interrupts: Demote kernel-doc formatting misuse

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

 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c:246: error: Cannot parse struct or union!
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_interrupts.c:756: error: Cannot parse struct or union!

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: Shubhashree Dhar <dhar@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>