configs/rdv2: enable ffa and sel3 spmc

Currently, the Secure partition is running at SEL0, and the NS world
uses the SPM_MM protocol for communication. The community and the
platform do not actively support this protocol. FF-A is introduced as
alternative.

Move RD-V2 platform to FF-A protocol by enabling SPMC build flags for
TF-A and enabling FFA build for edk2.

Signed-off-by: Nishant Sharma <nishant.sharma@arm.com>
Change-Id: I46b9c6a58c127584471b9f2d4463cdb43a7348e4