feat(rdv3r1): set CTX_INCLUDE_SVE_REGS build flag for RD-V3-R1 variants

Commit 42422622(feat(simd):add sve state to simd ctxt struct)
introduced the CTX_INCLUDE_SVE_REGS build flag that needs to be set
if SVE is enabled for more than one world, which is the case for
RD-V3-R1. This build flag enables SVE registers to be included when
saving and restoring the CPU context.

Signed-off-by: Lokesh B V <Lokesh.BV@Arm.com>
Change-Id: I903045519e1e5a9d33419982df4cc91b0683b4fc