selftests/ftrace: Add CONFIG_SAMPLE_FTRACE_DIRECT=m kconfig

ftrace-direct.tc and kprobe-direct.tc require CONFIG_SAMPLE_FTRACE_DIRECT=m
so add it to config file which is used by merge_config.sh.
Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/ftrace/config

@@ -11,5 +11,6 @@ CONFIG_PREEMPTIRQ_DELAY_TEST=m
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_SAMPLES=y
+CONFIG_SAMPLE_FTRACE_DIRECT=m
 CONFIG_SAMPLE_TRACE_PRINTK=m
 CONFIG_KALLSYMS_ALL=y