Add dummy RPC handler for RPCs that are not implemented as control
should be returned back to OP-TEE in case any RPC is invoked.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>