smb: client: compress: fix an "illegal accesses" issue

Using uninitialized value "bkt" when calling "kfree"

Fixes: 13b68d44990d ("smb: client: compress: LZ77 code improvements cleanup")
Signed-off-by: Qianqiang Liu <qianqiang.liu@163.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/client/compress.c

@@ -233,7 +233,7 @@ static int collect_sample(const struct iov_iter *iter, ssize_t max, u8 *sample)
 static int is_compressible(const struct iov_iter *data)
 {
 	const size_t read_size = SZ_2K, bkt_size = 256, max = SZ_4M;
-	struct bucket *bkt;
+	struct bucket *bkt = NULL;
 	int i = 0, ret = 0;
 	size_t len;
 	u8 *sample;