drm/amd/display: Copy AUX read reply data whenever length > 0

[Why]
amdgpu_dm_process_dmub_aux_transfer_sync() should return all exact data
reply from the sink side. Don't do the analysis job in it.

[How]
Remove unnecessary check condition AUX_TRANSACTION_REPLY_AUX_ACK.

Fixes: ead08b95 ("drm/amd/display: Fix race condition in DPIA AUX transfer")
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Ray Wu <ray.wu@amd.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>