refactor(ff-a): mem share helper change to test error returns

In order to test FF-A memory sharing operations in faulty cases we need
to be able to get the details of smc call failure in tftf and cactus.
Passes smc_ret_value in the relevant memory management test helpers.

Signed-off-by: Maksims Svecovs <maksims.svecovs@arm.com>
Change-Id: I81059b77cbb01fe9427905adbe262ba8d0670cee
4 files changed