selftests: add missing test result status in memory-hotplug test

it only prints FAIL status when test fails, but doesn't print PASS
status when test pass,this patch is to add PASS status in the test log.
Signed-off-by: Lei Yang <Lei.Yang@windriver.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/memory-hotplug/Makefile

@@ -4,10 +4,10 @@ all:
 include ../lib.mk
 
 TEST_PROGS := mem-on-off-test.sh
-override RUN_TESTS := ./mem-on-off-test.sh -r 2 || echo "selftests: memory-hotplug [FAIL]"
+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)"
 
 run_full_test:
-	@/bin/bash ./mem-on-off-test.sh || echo "memory-hotplug selftests: [FAIL]"
+	@/bin/bash ./mem-on-off-test.sh && echo "memory-hotplug selftests: [PASS]" || echo "memory-hotplug selftests: [FAIL]"
 
 clean: