selftests: memory-hotplug: fix emit_tests regression

Commit 16c513b13477
("selftests: memory-hotplug: silence test command echo")

introduced regression in emit_tests and results in the following
failure when selftests are installed and run. Fix it.

Running tests in memory-hotplug
========================================
./run_kselftest.sh: line 121: @./mem-on-off-test.sh: No such file or
directory
selftests: memory-hotplug [FAIL]

Fixes: 16c513b13477 (selftests: memory-hotplug: silence test command echo")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/memory-hotplug/Makefile

@@ -5,7 +5,8 @@ include ../lib.mk
 
 TEST_PROGS := mem-on-off-test.sh
 override RUN_TESTS := @./mem-on-off-test.sh -r 2 && echo "selftests: memory-hotplug [PASS]" || echo "selftests: memory-hotplug [FAIL]"
-override EMIT_TESTS := echo "$(RUN_TESTS)"
+
+override EMIT_TESTS := echo "$(subst @,,$(RUN_TESTS))"
 
 run_full_test:
 	@/bin/bash ./mem-on-off-test.sh && echo "memory-hotplug selftests: [PASS]" || echo "memory-hotplug selftests: [FAIL]"