qemu: fix "make check" to use OP-TEE image v2

Commit 37ab51d ("qemu: bios load OP-TEE image v2") has updated the run
and run-only targets, but not make check. Fix this.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
diff --git a/qemu.mk b/qemu.mk
index 13c1d3b..c0e6916 100644
--- a/qemu.mk
+++ b/qemu.mk
@@ -189,7 +189,9 @@
 endif
 
 check: $(CHECK_DEPS)
-	expect qemu-check.exp -- $(check-args) || \
+	cd $(BINARIES_PATH) && \
+		export QEMU=$(ROOT)/qemu/arm-softmmu/qemu-system-arm && \
+		expect $(ROOT)/build/qemu-check.exp -- $(check-args) || \
 		(if [ "$(DUMP_LOGS_ON_ERROR)" ]; then \
 			echo "== $$PWD/serial0.log:"; \
 			cat serial0.log; \