feat(optee): add loading OP-TEE image via an SMC

feat(optee): add loading OP-TEE image via an SMC

This adds the ability to load the OP-TEE image via an SMC called from
non-secure userspace rather than loading it during boot. This should
only be utilized on platforms that can ensure security is maintained up
until the point the SMC is invoked as it breaks the normal barrier
between the secure and non-secure world.

Signed-off-by: Jeffrey Kardatzke <jkardatzke@google.com>
Change-Id: I21cfa9699617c493fa4190f01d1cbb714e7449cc