drm/amdgpu: release correct lock in amdgpu_gfx_enable_kgq()

This function was releasing the incorrect lock on the error path.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 1156e1a6 ("drm/amdgpu: add [en/dis]able_kgq() functions")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -644,7 +644,7 @@ int amdgpu_gfx_enable_kgq(struct amdgpu_device *adev, int xcc_id)
 						adev->gfx.num_gfx_rings);
 		if (r) {
 			DRM_ERROR("Failed to lock KIQ (%d).\n", r);
-			spin_unlock(&adev->gfx.kiq[0].ring_lock);
+			spin_unlock(&kiq->ring_lock);
 			return r;
 		}