drm/amd/display: Decouple aux from i2c

[Why]
Aux engine is created from i2caux layer. We want to remove this layer
and use the engine directly.

[How]
Decouple aux engine from i2caux. Move aux engine related code to dce folder and use
dc resource pool to manage the engine. And use the engine functions directly

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>