selftests: livepatch: add new ftrace helpers functions

selftests: livepatch: add new ftrace helpers functions

Add new ftrace helpers functions cleanup_tracing, trace_function and
check_traced_functions.

Signed-off-by: Filipe Xavier <felipeaggger@gmail.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250324-ftrace-sftest-livepatch-v3-1-d9d7cc386c75@gmail.com
Signed-off-by: Petr Mladek <pmladek@suse.com>