tee: optee: define TEE error code TEE_ERROR_SHORT_BUFFER

Adds TEE_ERROR_SHORT_BUFFER as TEE error code. This error code is
commonly used by TEEs to inform caller that the buffer(s) it provided
is too small for the desired operation.

Cc: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>