feat(el3-spmc): add support for FFA_MEM_PERM_GET and SET ABIs

Secure partition running at SEL0 does not have privilege to modify
translation tables. So it needs SPMC to map the regions for it. Add the
support to request memory map or region info using  FF-A interface.

Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Change-Id: I04a97899808bbd45eda24edf7bc74eaef96fb2ce