drm/amd/display: Destroy connector state on reset

When a DRM mode reset is called on resume, the connector state's
destructor is not called. This leaves a dangling reference on the CRTC
commit object, which was obtained by the connector state during commit
setup.

Signed-off-by: Leo (Sunpeng) Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>