commit fb9a5b0c upstream.

Limit clocks on a specific HD86xx part to avoid
crashes (while awaiting an appropriate PP fix).
Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>