qemu_v8: use QEMU_VIRT in check target

Export QEMU_VIRT in the check target and update the expect script to use
QEMU_VIRT when adding the "virtualization" to QEMU. This enables the
check target with Hafnium, that is, SPMC_AT_EL=2.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
diff --git a/qemu_v8.mk b/qemu_v8.mk
index 92702e0..74515f3 100644
--- a/qemu_v8.mk
+++ b/qemu_v8.mk
@@ -508,6 +508,7 @@
 		export QEMU_GIC=$(QEMU_GIC_VERSION) && \
 		export QEMU_MEM=$(QEMU_MEM) && \
 		export QEMU_CPU=$(QEMU_CPU) && \
+		export QEMU_VIRT=$(QEMU_VIRT) && \
 		export XEN_BOOT=$(XEN_BOOT) && \
 		expect $(ROOT)/build/qemu-check.exp -- $(check-args) || \
 		(if [ "$(DUMP_LOGS_ON_ERROR)" ]; then \