drm/amd/display/dc/core/dc_resource: Demote some kernel-doc abuses

drm/amd/display/dc/core/dc_resource: Demote some kernel-doc abuses

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

 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1710: warning: Function parameter or member 'old_stream' not described in 'dc_is_stream_unchanged'
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1710: warning: Function parameter or member 'stream' not described in 'dc_is_stream_unchanged'
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1726: warning: Function parameter or member 'old_stream' not described in 'dc_is_stream_scaling_unchanged'
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1726: warning: Function parameter or member 'stream' not described in 'dc_is_stream_scaling_unchanged'
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1843: warning: Function parameter or member 'dc' not described in 'dc_add_stream_to_ctx'
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1843: warning: Function parameter or member 'new_ctx' not described in 'dc_add_stream_to_ctx'
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1843: warning: Function parameter or member 'stream' not described in 'dc_add_stream_to_ctx'
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1870: warning: Function parameter or member 'dc' not described in 'dc_remove_stream_from_ctx'
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1870: warning: Function parameter or member 'new_ctx' not described in 'dc_remove_stream_from_ctx'
 drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_resource.c:1870: warning: Function parameter or member 'stream' not described in 'dc_remove_stream_from_ctx'

Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>