lib/decompress_unlz4.c: always set an error return code on failures

"ret", being set to -1 early on, gets cleared by the first invocation of
lz4_decompress()/lz4_decompress_unknownoutputsize(), and hence subsequent
failures wouldn't be noticed by the caller without setting it back to -1
right after those calls.

Reported-by: Matthew Daley <[email protected]>
Signed-off-by: Jan Beulich <[email protected]>
Cc: Kyungsik Lee <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

lib/decompress_unlz4.c

@@ -141,6 +141,7 @@ STATIC inline int INIT unlz4(u8 *input, int in_len,
 			goto exit_2;
 		}
 
+		ret = -1;
 		if (flush && flush(outp, dest_len) != dest_len)
 			goto exit_2;
 		if (output)