drm/msm/disp/dpu1/dpu_hw_blk: Add one missing and remove an extra param description

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

 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_blk.c:28: warning: Function parameter or member 'hw_blk' not described in 'dpu_hw_blk_init'
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_blk.c:120: warning: Excess function parameter 'free_blk' description in 'dpu_hw_blk_put'

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: 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>