mISDN: DSP now uses ring buffer for echo canceler

DSP now uses ring buffer for echo canceler.
Added missing include in l1oip_codec.c

Signed-off-by: Andreas Eversberg <andreas@eversberg.eu>
Signed-off-by: Karsten Keil <keil@b1-systems.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/isdn/mISDN/dsp.h b/drivers/isdn/mISDN/dsp.h
index 98a33c58f..0a4a362 100644
--- a/drivers/isdn/mISDN/dsp.h
+++ b/drivers/isdn/mISDN/dsp.h
@@ -112,7 +112,8 @@
 
 #define DSP_DTMF_NPOINTS 102
 
-#define ECHOCAN_BUFLEN (4*128)
+#define ECHOCAN_BUFF_SIZE 0x400 /* must be 2**n */
+#define ECHOCAN_BUFF_MASK 0x3ff /* -1 */
 
 struct dsp_dtmf {
 	int		treshold; /* above this is dtmf (square of) */