drm/radeon: fix up dp aux tear down (v2)

Port the amdgpu fixes from Grazvydas to radeon.

v2: drop unrelated whitespace change.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=98200

Reviewed-and-Tested-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_i2c.c

@@ -982,9 +982,8 @@ void radeon_i2c_destroy(struct radeon_i2c_chan *i2c)
 {
 	if (!i2c)
 		return;
+	WARN_ON(i2c->has_aux);
 	i2c_del_adapter(&i2c->adapter);
-	if (i2c->has_aux)
-		drm_dp_aux_unregister(&i2c->aux);
 	kfree(i2c);
 }