drm/amdgpu/pm/smu7: drop message about VI performance levels

Earlier chips only had two performance levels, but newer
ones potentially had more.  The message is harmless.  Drop the
message to avoid spamming the log.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1874


Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>