selftests: mqueue: fix regression in silencing output from RUN_TESTS

Fix fix regression in silencing output from RUN_TESTS introduced by
commit <8230b905a6780c6> selftests: mqueue: Use full path to run tests
from Makefile

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/mqueue/Makefile

@@ -5,8 +5,8 @@ TEST_GEN_PROGS := mq_open_tests mq_perf_tests
 include ../lib.mk
 
 override define RUN_TESTS
-	$(OUTPUT)/mq_open_tests /test1 || echo "selftests: mq_open_tests [FAIL]"
-	$(OUTPUT)//mq_perf_tests || echo "selftests: mq_perf_tests [FAIL]"
+	@$(OUTPUT)/mq_open_tests /test1 || echo "selftests: mq_open_tests [FAIL]"
+	@$(OUTPUT)/mq_perf_tests || echo "selftests: mq_perf_tests [FAIL]"
 endef
 
 override define EMIT_TESTS