drm/amd/display: not skip hpd irq for bw alloc mode

drm/amd/display: not skip hpd irq for bw alloc mode

[WHY]
Driver only process hpd irq when a branch device or when
the link is established. It would cause some irq for bw_alloc
mode of dp tunneling are ignored.

[HOW]
Driver should process hpd irq if bw_alloc and dp tunneling
are enabled.

Reviewed-by: Cruise Hung <cruise.hung@amd.com>
Signed-off-by: Peichen Huang <PeiChen.Huang@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>