tee: optee: update optee_msg.h and optee_smc.h to dual license

The files optee_msg.h and optee_smc.h (under drivers/tee/optee) contain
information originating from the OP-TEE OS project [1] [2], where the
licensing terms are BSD 2-Clause. Therefore, apply a dual license to
those files.

Link: [1] https://github.com/OP-TEE/optee_os/blob/master/core/include/optee_msg.h
Link: [2] https://github.com/OP-TEE/optee_os/blob/master/core/arch/arm/include/sm/optee_smc.h


Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>