drm/amd/pm: fix smu v13 soft clock frequency setting issue

drm/amd/pm: fix smu v13 soft clock frequency setting issue

commit c764b7af15289051718b4859a67f9a3bc69d3fb2 upstream.

v1:
resolve the issue where some freq frequencies cannot be set correctly
due to insufficient floating-point precision.

v2:
patch this convert on 'max' value only.

Signed-off-by: Yang Wang <kevinyang.wang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 6194f60c707e3878e120adeb36997075664d8429)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>