drm/amdgpu/atom: add SetDCEClock helper

New cmd table for ELM/BAF for setting the dispclock or
dprefclock.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_crtc.h b/drivers/gpu/drm/amd/amdgpu/atombios_crtc.h
index c670833..0eeda8e 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_crtc.h
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_crtc.h
@@ -37,6 +37,8 @@
 				  struct drm_display_mode *mode);
 void amdgpu_atombios_crtc_set_disp_eng_pll(struct amdgpu_device *adev,
 				    u32 dispclk);
+u32 amdgpu_atombios_crtc_set_dce_clock(struct amdgpu_device *adev,
+				       u32 freq, u8 clk_type, u8 clk_src);
 void amdgpu_atombios_crtc_program_pll(struct drm_crtc *crtc,
 			       u32 crtc_id,
 			       int pll_id,