drm/amd/pm: Update emit clock logic

drm/amd/pm: Update emit clock logic

If only one level is enabled in clock table, there is no need to
follow the fine grained clock logic which expects a minimum of
two levels (min/max).

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Asad Kamal <asad.kamal@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>