drm/amd/display: make clk_mgr call enable_pme_wa

refactor a code so we will call clk_mgr's enable_pme_wa function so we
can use pme_wa for future asics. This way we don't need to worry about
different ASIC since clk_mgr already have that information

Signed-off-by: Su Sung Chung <Su.Chung@amd.com>
Reviewed-by: Eric Yang <eric.yang2@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>