drm/amd/pm: add sysfs node vclk1 and dclk1

User can check pp_dpm_vclk1 and pp_dpm_dclk1 for DPM frequency of
vcn and dcn

Signed-off-by: Tong Liu01 <Tong.Liu01@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>