drm/amd|radeon: Drop drm_vblank_cleanup

Both drivers shut down all crtc beforehand already, which will shut up
any pending vblank (the only thing vblank_cleanup really does is
disable the disable timer). Hence we don't need this here and can
remove it.

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170621082850.13224-2-daniel.vetter@ffwll.ch

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

@@ -262,7 +262,6 @@ void amdgpu_irq_fini(struct amdgpu_device *adev)
 {
 	unsigned i, j;
 
-	drm_vblank_cleanup(adev->ddev);
 	if (adev->irq.installed) {
 		drm_irq_uninstall(adev->ddev);
 		adev->irq.installed = false;

drivers/gpu/drm/radeon/radeon_irq_kms.c

@@ -324,7 +324,6 @@ int radeon_irq_kms_init(struct radeon_device *rdev)
  */
 void radeon_irq_kms_fini(struct radeon_device *rdev)
 {
-	drm_vblank_cleanup(rdev->ddev);
 	if (rdev->irq.installed) {
 		drm_irq_uninstall(rdev->ddev);
 		rdev->irq.installed = false;