tests/tcg: add QEMU_OPT option for test runner

This will allow tests to modify the QEMU invocation with for example
different -cpu stazas without having to define a whole new set of
runner types.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/tests/tcg/Makefile b/tests/tcg/Makefile
index 55feab0..454d0a4 100644
--- a/tests/tcg/Makefile
+++ b/tests/tcg/Makefile
@@ -54,10 +54,13 @@
 # The QEMU for this TARGET
 ifdef CONFIG_USER_ONLY
 QEMU=../qemu-$(TARGET_NAME)
+QEMU_OPTS=
 else
 QEMU=../qemu-system-$(TARGET_NAME)
+QEMU_OPTS=-monitor none -display none
 endif
 
+
 # If TCG debugging is enabled things are a lot slower
 ifeq ($(CONFIG_DEBUG_TCG),y)
 TIMEOUT=45
@@ -108,7 +111,7 @@
 RUN_TESTS+=$(EXTRA_RUNS)
 
 run-%: %
-	$(call run-test, $<, $(QEMU) $<, "$< on $(TARGET_NAME)")
+	$(call run-test, $<, $(QEMU) $(QEMU_OPTS) $<, "$< on $(TARGET_NAME)")
 
 .PHONY: run
 run: $(RUN_TESTS)