drm/amd/display: i2c/aux Remove link index.

Link index is an unnecessery level of inderection when
calling from kernel i2c/aux transfer into DAL.

Signed-off-by: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>