Make supported FF-A version configurable in libsp

Introduce CFG_FFA_VERSION macro for configuring FF-A version in libsp.
The value of CFG_FFA_VERSION follows the version format of FFA_VERSION.
The allowed versions are FF-A v1.0 and v1.1.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: I7f2b425f9267758c4dfec513bc7a3bde773c7a97
8 files changed