drm/amd/display: Update number of DCN3 clock states

commit 0bbf06d8 upstream.

[Why & How]
The DCN3 SoC parameter num_states was calculated but not saved into the
object.

Bug: amd#1403


Cc: stable@vger.kernel.org
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>