automation: qemu-smoke-arm64.sh: Fix the number of cpus in the device tree

Qemu VM is configured with 2 cpus but the device tree passed has only 1.
Generate a device tree with 2 cpus.

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

automation/scripts/qemu-smoke-arm64.sh

@@ -35,7 +35,7 @@ curl -fsSLO https://github.com/qemu/qemu/raw/v5.2.0/pc-bios/efi-virtio.rom
 ./binaries/qemu-system-aarch64 \
    -machine virtualization=true \
    -cpu cortex-a57 -machine type=virt \
-   -m 1024 -display none \
+   -m 1024 -smp 2 -display none \
    -machine dumpdtb=binaries/virt-gicv2.dtb
 # XXX disable pl061 to avoid Linux crash
 dtc -I dtb -O dts binaries/virt-gicv2.dtb > binaries/virt-gicv2.dts