feat(fvp): added calls to unprotect/protect memory

Added SiP calls to FVP platform to protect/unprotect a
memory range.
These leverage rme features to change the PAS of a given
memory range from non-secure to secure.

The mentioned call is leveraged by the SPMC in the memory
sharing flow, when memory is shared from the normal world
onto the secure world.

More details in the SPM related patches.

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: Iaf15d8603a549d247ffb1fc14c16bfb94d0e178a
4 files changed