drivers: tee: optee: discover OP-TEE services

This change defines resources for OP-TEE service drivers to register
themselves for being bound to when OP-TEE firmware reports the related
service is supported. OP-TEE services are discovered during optee
driver probe sequence which mandates optee driver is always probe once
bound.

Discovery of optee services and binding to related U-Boot drivers is
embedded upon configuration switch CONFIG_OPTEE_SERVICE_DISCOVERY.

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