drm/amdgpu: free hw_vm_fence when fail in amdgpu_job_alloc

If drm_sched_job_init fails, hw_vm_fence is not freed currently,
then cause memory leak.

Fixes: db36632 ("drm/amdgpu: clean up and unify hw fence handling")
Link: https://lore.kernel.org/amd-gfx/a5a828cb-0e4a-41f0-94c3-df31e5ddad52@amd.com/T/#t
Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
Reviewed-by: Amos Kong <kongjianjun@gmail.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 5d42ee4)

Author: Jiqian Chen

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

@@ -217,8 +217,11 @@ int amdgpu_job_alloc(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 	if (!entity)
 		return 0;
 
-	return drm_sched_job_init(&(*job)->base, entity, 1, owner,
-				  drm_client_id);
+	r = drm_sched_job_init(&(*job)->base, entity, 1, owner, drm_client_id);
+	if (!r)
+		return 0;
+
+	kfree((*job)->hw_vm_fence);
 
 err_fence:
 	kfree((*job)->hw_fence);