Currently, RiscVVirtQemu supports unified code and variable store mainly because only one pflash devices was available in qemu for EDK2. However, this doesn't allow to map the code part as read-only. With recent qemu enhancements, it is now possible for EDK2 to make use of both pflash devices in RISC-V virt machine. So, add support to create code and vars images separately. This also allows easy firmware code updates without losing the variable store. Signed-off-by: Sunil V L <sunilvl@ventanamicro.com> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Andrei Warkentin <andrei.warkentin@intel.com> Cc: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>