cpu-hotplug selftests: print failure status instead of cause make error

Original behavior:
bash-4.1$ make -C cpu-hotplug run_tests
make: Entering directory `/home/dave/git/linux-2.6/tools/testing/selftests/cpu-hotplug'
./on-off-test.sh
make: execvp: ./on-off-test.sh: Permission denied
make: *** [run_tests] Error 127
make: Leaving directory `/home/dave/git/linux-2.6/tools/testing/selftests/cpu-hotplug'

After applying the patch:
bash-4.1$ make -C cpu-hotplug run_tests
make: Entering directory `/home/dave/git/linux-2.6/tools/testing/selftests/cpu-hotplug'
/bin/sh: ./on-off-test.sh: Permission denied
cpu-hotplug selftests: [FAIL]
make: Leaving directory `/home/dave/git/linux-2.6/tools/testing/selftests/cpu-hotplug'

Signed-off-by: Dave Young <[e-mail]>
Reviewed-by: Pekka Enberg <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

tools/testing/selftests/cpu-hotplug/Makefile

···
 all:
 
 run_tests:
-	./on-off-test.sh
+	@./on-off-test.sh || echo "cpu-hotplug selftests: [FAIL]"
 
 clean: