drm/amd/display: make enable link independent from verified link caps

[why]
Ideally link capability should be independent from the link
configuration that we decide to use in enable link. Otherwise if link
capability is changed after validation has completed, we could end up
enabling a link configuration with invalid configuration. This would
lead to over link bandwidth subscription or in the extreme case
causes us to enable HPO link to a DIO stream.

[how]
Add a new struct in pipe ctx called link config. This structure will
contain link configuration to enable a link. It will be populated
during map pool resources after we validate link bandwidth. Remove
the reference of verified link cap during enable link process and
use link config in pipe ctx instead.

Reviewed-by: George Shen <George.Shen@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>