commit 0b10029d upstream.

This was accidently broken for harvest cards when the
code was refactored for Polaris support.

v2: multiply by shader engines.  Noticed by Nicolai.
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>