qemu, qemu_v8: set QEMU_SMP ?= 2

Use two vCPUs by default instead of one. This configuration is more
likely to trigger race conditions when testing.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/qemu_v8.mk b/qemu_v8.mk
index 50af414..9c9a44c 100644
--- a/qemu_v8.mk
+++ b/qemu_v8.mk
@@ -154,7 +154,7 @@
 run: all
 	$(MAKE) run-only
 
-QEMU_SMP ?= 1
+QEMU_SMP ?= 2
 
 .PHONY: run-only
 run-only: