avalon_cts use correct buffer
diff --git a/driver-avalon.c b/driver-avalon.c
index d159711..481d2c2 100644
--- a/driver-avalon.c
+++ b/driver-avalon.c
@@ -252,7 +252,7 @@ static int avalon_read(struct cgpu_info *avalon, unsigned char *buf,
/* Use the fact that we're reading the status with the buffer to tell
* the write thread it should send more work without needing to call
* avalon_buffer_full directly. */
- if (avalon_cts(buf[0]))
+ if (avalon_cts(readbuf[0]))
cgsem_post(&info->write_sem);
/* The first 2 of every 64 bytes are status on FTDIRL */