drm/amdgpu: drop flood print in rlcg reg access function

A lot of below message are outputed in SRIOV case.
amdgpu: indirect registers access through rlcg is not supported

Also drop redundant ret set, as it's initialized to be false already.

Fixes: 29dbcac8 ("drm/amdgpu: add helper to query rlcg reg access flag")
Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>