drm/msm/disp/dpu1/dpu_plane: Fix some spelling and missing function param descriptions

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

 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:152: warning: Function parameter or member 'plane' not described in '_dpu_plane_calc_bw'
 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:152: warning: Function parameter or member 'fb' not described in '_dpu_plane_calc_bw'
 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:152: warning: Excess function parameter 'Plane' description in '_dpu_plane_calc_bw'
 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:200: warning: Function parameter or member 'plane' not described in '_dpu_plane_calc_clk'
 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:200: warning: Excess function parameter 'Plane' description in '_dpu_plane_calc_clk'
 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:232: warning: Function parameter or member 'src_width' not described in '_dpu_plane_calc_fill_level'
 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:232: warning: Excess function parameter 'src_wdith' description in '_dpu_plane_calc_fill_level'
 drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:1060: warning: Function parameter or member 'error' not described in 'dpu_plane_set_error'

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>