[WHY]
To enable dc links for USB4 DPIA ports and AUX command tunneling
for YELLOW_CARP_B0.

[HOW]
1) Created dc links for all USB4 DPIA ports in create_links().
   dc_link_construct() implementation is split for legacy DDC and DPIAs.
   As usb4 has no ddc, ddc->ddc_pin will be set to NULL for its dc link
   and this parameter will be used to identify the dc links as DPIA. The
   dc link for DPIA is further to be enhanced with implementation for link
   encoder and link initialization.
2) usb4_dpia_count in struct resource_pool will be initialized to 4 in
   dcn31_resource_construct() if the DCN is YELLOW_CARP_B0.
3) Enabled DMUB AUX via outbox for YELLOW_CARP_B0.
Reviewed-by: Jimmy Kizito <Jimmy.Kizito@amd.com>
Acked-by: Wayne Lin <Wayne.Lin@amd.com>
Acked-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>