drm/amd/display/dc/dce/dmub_psr: Demote non-conformant kernel-doc headers

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

 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:38: warning: Function parameter or member 'raw_state' not described in 'convert_psr_state'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:81: warning: Function parameter or member 'dmub' not described in 'dmub_psr_get_state'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:81: warning: Function parameter or member 'state' not described in 'dmub_psr_get_state'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:97: warning: Function parameter or member 'dmub' not described in 'dmub_psr_set_version'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:97: warning: Function parameter or member 'stream' not described in 'dmub_psr_set_version'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:128: warning: Function parameter or member 'dmub' not described in 'dmub_psr_enable'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:128: warning: Function parameter or member 'enable' not described in 'dmub_psr_enable'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:128: warning: Function parameter or member 'wait' not described in 'dmub_psr_enable'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:177: warning: Function parameter or member 'dmub' not described in 'dmub_psr_set_level'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:177: warning: Function parameter or member 'psr_level' not described in 'dmub_psr_set_level'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:203: warning: Function parameter or member 'dmub' not described in 'dmub_psr_copy_settings'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:203: warning: Function parameter or member 'link' not described in 'dmub_psr_copy_settings'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:203: warning: Function parameter or member 'psr_context' not described in 'dmub_psr_copy_settings'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:284: warning: Function parameter or member 'dmub' not described in 'dmub_psr_force_static'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:301: warning: Function parameter or member 'dmub' not described in 'dmub_psr_get_residency'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:301: warning: Function parameter or member 'residency' not described in 'dmub_psr_get_residency'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:323: warning: Function parameter or member 'psr' not described in 'dmub_psr_construct'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:323: warning: Function parameter or member 'ctx' not described in 'dmub_psr_construct'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:332: warning: Function parameter or member 'ctx' not described in 'dmub_psr_create'
 drivers/gpu/drm/amd/amdgpu/../display/dc/dce/dmub_psr.c:349: warning: Function parameter or member 'dmub' not described in 'dmub_psr_destroy'

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: Wyatt Wood <wyatt.wood@amd.com>
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>