btrfs: Remove unused tot_len var from lzo_decompress

Added already unused in a6fa6fae40ec ("btrfs: Add lzo compression
support").

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/lzo.c

@@ -382,14 +382,12 @@ static int lzo_decompress(struct list_head *ws, unsigned char *data_in,
 	struct workspace *workspace = list_entry(ws, struct workspace, list);
 	size_t in_len;
 	size_t out_len;
-	size_t tot_len;
 	int ret = 0;
 	char *kaddr;
 	unsigned long bytes;
 
 	BUG_ON(srclen < LZO_LEN);
 
-	tot_len = read_compress_length(data_in);
 	data_in += LZO_LEN;
 
 	in_len = read_compress_length(data_in);