ftrace: Simplify glob handling in unregister_ftrace_function_probe_func()

Handle a NULL glob properly and simplify the check.

Link: http://lkml.kernel.org/r/5df74d4ffb4721db6d5a22fa08ca031d62ead493.1494956770.git.naveen.n.rao@linux.vnet.ibm.com

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/ftrace.c

@@ -4144,9 +4144,9 @@ unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
 	int i, ret = -ENODEV;
 	int size;
 
-	if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
+	if (!glob || !strlen(glob) || !strcmp(glob, "*"))
 		func_g.search = NULL;
-	else if (glob) {
+	else {
 		int not;
 
 		func_g.type = filter_parse_regex(glob, strlen(glob),