drm/amd/powerplay: add function to set min dcef deep sleep for smu11 (v2)

Add smu_v11_0_set_min_dcef_deep_sleep function for smu11.

v2: fix coding error about set_min_dcef_deep_sleep (Kevin)

Signed-off-by: Kevin Wang <Kevin1.Wang@amd.com>
Signed-off-by: Likun Gao <Likun.Gao@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Kevin Wang <Kevin1.Wang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>