drm/amdgpu: Fix potential uninitialized use of 'idle' in amdgpu_ids.c

v2: Use NULL and reverse christmas tree ordering
Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -406,7 +406,8 @@ int amdgpu_vmid_grab(struct amdgpu_vm *vm, struct amdgpu_ring *ring,
 	struct amdgpu_device *adev = ring->adev;
 	unsigned vmhub = ring->funcs->vmhub;
 	struct amdgpu_vmid_mgr *id_mgr = &adev->vm_manager.id_mgr[vmhub];
-	struct amdgpu_vmid *id, *idle;
+	struct amdgpu_vmid *idle = NULL;
+	struct amdgpu_vmid *id = NULL;
 	int r = 0;
 
 	mutex_lock(&id_mgr->lock);