selftests/ftrace: Add kprobe-event with symbol argument test

Add a testcase for kprobe-event with @symbol argument.
Since @symbol needs to refer the kernel data symbol
(linux_proc_banner), it requires CONFIG_KALLSYMS_ALL.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>