[Why]
Observe error message "Can't retrieve aconnector in hpd_rx_irq_offload_work"
when boot up with a mst tbt4 dock connected. After analyzing, there are few
parts needed to be adjusted:

1. hpd_rx_offload_wq[].aconnector is not initialzed before the dmub outbox
hpd_irq handler get registered which causes the error message.

2. registeration of hpd and hpd_rx_irq event for usb4 dp tunneling is not
aligned with legacy interface sequence

[How]
Put DMUB_NOTIFICATION_HPD and DMUB_NOTIFICATION_HPD_IRQ handler
registration into register_hpd_handlers() to align other interfaces and
get hpd_rx_offload_wq[].aconnector initialized earlier than that.

Leave DMUB_NOTIFICATION_AUX_REPLY registered as it was since we need that
while calling dc_link_detect(). USB4 connection status will be proactively
detected by dc_link_detect_connection_type() in amdgpu_dm_initialize_drm_device()

Cc: Stable <stable@vger.kernel.org>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Acked-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>