bpf: Initialize ret to 0 inside btf_populate_kfunc_set()

Kernel test robot reported below error ->

kernel/bpf/btf.c:6718 btf_populate_kfunc_set()
error: uninitialized symbol 'ret'.

Initialize ret to 0.

Fixes: dee872e1 ("bpf: Populate kfunc BTF ID sets in struct btf")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20220219163915.125770-1-jrdr.linux@gmail.com

kernel/bpf/btf.c

@@ -6706,7 +6706,7 @@ static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
 				  const struct btf_kfunc_id_set *kset)
 {
 	bool vmlinux_set = !btf_is_module(btf);
-	int type, ret;
+	int type, ret = 0;
 
 	for (type = 0; type < ARRAY_SIZE(kset->sets); type++) {
 		if (!kset->sets[type])