drm/amd/display: reallocate MST payload when link loss

[Why]
Try to allocate MST payload but receive HPD short pulse with link loss
casue driver allocate payload twice. It cause monitor can't light up
successfully.

[How]
When driver receive HPD short pulse with link loss, we need to
deallocate payload then allocate payload.
Then we will not allocate payload twice with same sink.

Signed-off-by: Paul Hsieh <paul.hsieh@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>