drm/radeon: don't share PPLLs on DCE4.1

commit 70471860ff9f335c60c004d42ebd48945bfa5403 upstream.

Sharing PPLLs seems to cause problems on some boards.

Bug:
https://bugs.freedesktop.org/show_bug.cgi?id=45334



Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>