drm/amd/powerplay: drop smu_v12_0.c unnecessary wrapper V2

drm/amd/powerplay: drop smu_v12_0.c unnecessary wrapper V2

By moving the implemention to renoir_ppt.c considering
it's really ASIC specific.

V2: fix compile warnings below
drivers/gpu/drm/amd/amdgpu/../powerplay/renoir_ppt.h:40:25: warning: array subscript is above array bounds [-Warray-bounds]
    freq = table->FClocks[dpm_level].Freq; \
drivers/gpu/drm/amd/amdgpu/../powerplay/renoir_ppt.c:195:2: note: in expansion of macro ‘GET_DPM_CUR_FREQ’
  GET_DPM_CUR_FREQ(clk_table, clk_type, dpm_level, *freq);
  ^~~~~~~~~~~~~~~~
drivers/gpu/drm/amd/amdgpu/../powerplay/renoir_ppt.h:46:25: warning: array subscript is above array bounds [-Warray-bounds]
    freq = table->FClocks[dpm_level].Freq;  \
drivers/gpu/drm/amd/amdgpu/../powerplay/renoir_ppt.c:195:2: note: in expansion of macro ‘GET_DPM_CUR_FREQ’
  GET_DPM_CUR_FREQ(clk_table, clk_type, dpm_level, *freq);

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