drm/amdgpu/virt: fix double kfree on bo_va

bo_va is being kfree'd twice, once in the call to amdgpu_vm_bo_rmv
and then a short while later. Fix this double free by removing
the 2nd kfree.

Detected by CoverityScan, CID#1399524 ("Double Free")
Reviewed-by: NMonk Liu <monk.liu@amd.com>
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

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

@@ -83,7 +83,6 @@ int amdgpu_map_static_csa(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 		DRM_ERROR("failed to do bo_map on static CSA, err=%d\n", r);
 		amdgpu_vm_bo_rmv(adev, bo_va);
 		ttm_eu_backoff_reservation(&ticket, &list);
-		kfree(bo_va);
 		return r;
 	}