On SI asics, the SMC will automatically force the performance
level to the lowest level if there are no displays active.  This
prevents automatic performance scaling on PowerXpress systems or
for offscreen rendering or compute when displays are disabled.

Going forward, it would be best to dynamically change this, but
for now leave scaling enabled.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=69395Signed-off-by: Alex Deucher <alexander.deucher@amd.com>