drm/radeon/dpm: remove local sumo_get_xclk()

Use the new asic callback instead.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --cc drivers/gpu/drm/radeon/sumo_dpm.c
Simple merge

diff --cc drivers/gpu/drm/radeon/sumo_dpm.h
Simple merge

diff --cc drivers/gpu/drm/radeon/sumo_smc.c
Simple merge

diff --cc drivers/gpu/drm/radeon/trinity_dpm.c
Simple merge