drm/amd/display: Remove redundant i2c structs

[Why]
The i2c code contains two structs that contain the same
information as i2c_payload

[How]
Replace references to those structs with references to
i2c_payload

dce_i2c_transaction_request->status was written to but never read,
so all references to it are removed

Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Jordan Lazare <Jordan.Lazare@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>