Increase LCHAN_RELEASE_TIMEOUT to 10 seconds

If we release the LCHAN after the CM SERVICE ACK too early, we can no longer
receive longer SMS messages... so let's increase it to 10 secs.
diff --git a/openbsc/include/openbsc/gsm_data.h b/openbsc/include/openbsc/gsm_data.h
index cc92a9e..fcc1f2c 100644
--- a/openbsc/include/openbsc/gsm_data.h
+++ b/openbsc/include/openbsc/gsm_data.h
@@ -67,7 +67,7 @@
  * Use the channel. As side effect the lchannel recycle timer
  * will be started.
  */
-#define LCHAN_RELEASE_TIMEOUT 4, 0
+#define LCHAN_RELEASE_TIMEOUT 10, 0
 #define use_lchan(lchan) \
 	do {	lchan->use_count++; \
 		DEBUGP(DCC, "lchan (bts=%d,trx=%d,ts=%d,ch=%d) increases usage to: %d\n", \