meson.build: Declare global edk2_targets / install_edk2_blobs variables

Globally declare in the main meson.build:
- the list of EDK2 targets,
- whether the EDK2 blobs have to be installed.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210114174509.2944817-2-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
3 files changed