libbpf: Simplify the find_elf_sec_sz() function

The check in the last return statement is unnecessary, we can just return
the ret variable.

But we can simplify the function further by returning 0 immediately if we
find the section size and -ENOENT otherwise.

Thus we can also remove the ret variable.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>

tools/lib/bpf/libbpf.c

@@ -1374,22 +1374,20 @@ static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
 
 static int find_elf_sec_sz(const struct bpf_object *obj, const char *name, __u32 *size)
 {
-	int ret = -ENOENT;
 	Elf_Data *data;
 	Elf_Scn *scn;
 
-	*size = 0;
 	if (!name)
 		return -EINVAL;
 
 	scn = elf_sec_by_name(obj, name);
 	data = elf_sec_data(obj, scn);
 	if (data) {
-		ret = 0; /* found it */
 		*size = data->d_size;
+		return 0; /* found it */
 	}
 
-	return *size ? 0 : ret;
+	return -ENOENT;
 }
 
 static int find_elf_var_offset(const struct bpf_object *obj, const char *name, __u32 *off)