drm/amd/display: Keep disable aux-i delay as 0

[WHY]
Current Aux-I sequence checks for local_sink which isn't populated on
MST links

[HOW]
Leave disable aux-i delay as 0 for MST cases

Cc: stable@vger.kernel.org
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: George Shen <George.Shen@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Michael Strauss <michael.strauss@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>