drm/amdgpu/virtual_dce: drop empty function

No need to ack non-existent interrupts.
Reviewed-By: Emily Deng <Emily.Deng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/dce_virtual.c

@@ -707,15 +707,6 @@ static int dce_virtual_set_crtc_irq_state(struct amdgpu_device *adev,
 	return 0;
 }
 
-static void dce_virtual_crtc_vblank_int_ack(struct amdgpu_device *adev,
-					  int crtc)
-{
-	if (crtc >= adev->mode_info.num_crtc) {
-		DRM_DEBUG("invalid crtc %d\n", crtc);
-		return;
-	}
-}
-
 static int dce_virtual_crtc_irq(struct amdgpu_device *adev,
 			      struct amdgpu_irq_src *source,
 			      struct amdgpu_iv_entry *entry)
@@ -723,8 +714,6 @@ static int dce_virtual_crtc_irq(struct amdgpu_device *adev,
 	unsigned crtc = 0;
 	unsigned irq_type = AMDGPU_CRTC_IRQ_VBLANK1;
 
-	dce_virtual_crtc_vblank_int_ack(adev, crtc);
-
 	if (amdgpu_irq_enabled(adev, source, irq_type)) {
 		drm_handle_vblank(adev->ddev, crtc);
 	}