OP-TEE cleanup

- Remove a redundant custom workqueue in the OP-TEE driver.
- Fix a missing description of an argument to optee_handle_rpc().
-----BEGIN PGP SIGNATURE-----
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=wAS6
-----END PGP SIGNATURE-----