ftrace: Simplify ftrace hash lookup code in clear_func_from_hash()

Function ftrace_lookup_ip() will check empty hash table. So we don't
need extra check outside.

Link: http://lkml.kernel.org/r/[email protected]

Signed-off-by: Changbin Du <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>

Author: changbindu

kernel/trace/ftrace.c

@@ -6036,11 +6036,7 @@ clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
 {
 	struct ftrace_func_entry *entry;
 
-	if (ftrace_hash_empty(hash))
-		return;
-
-	entry = __ftrace_lookup_ip(hash, func->ip);
-
+	entry = ftrace_lookup_ip(hash, func->ip);
 	/*
 	 * Do not allow this rec to match again.
 	 * Yeah, it may waste some memory, but will be removed