drm/amd/display: Don't set cursor address is 0 logging as errors

This actually happens quite a bit, and having it as an error causes
false positive messages when running tests.

Signed-off-by: Andrew Jiang <Andrew.Jiang@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>