drm/amd/pm: remove logically dead code for renoir

The switch governing value clk_type cannot be SMU_GFXCLK and SMU_SCLK.

Fixes: ca55f459 ("drm/amd/pm: add the fine grain tuning function for Renoir")
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Reviewed-by: Yang Wang <kevinyang.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>