tests/tcg: ensure we re-configure if configure.sh is updated

We were only doing this if docker was enabled which isn't quite right.

Fixes: fc76c56
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20191211170520.7747-17-alex.bennee@linaro.org>

tests/tcg/Makefile.prereqs

@@ -13,6 +13,6 @@ DOCKER_IMAGE:=
 
 ifneq ($(DOCKER_IMAGE),)
 build-tcg-tests-$(PROBE_TARGET): docker-image-$(DOCKER_IMAGE)
+endif
 $(BUILD_DIR)/tests/tcg/config_$(PROBE_TARGET).mak: config-host.mak
 config-host.mak: $(SRC_PATH)/tests/tcg/configure.sh
-endif