improve echo calibration

[linphone] / mediastreamer2

diff --git a/mediastreamer2 b/mediastreamer2
index 756a51419d833105a6378db71679073f6e9492b0..73f3e2580927705f26a8eb2e98d8e15606ec6148 160000 (submodule)
--- a/mediastreamer2
+++ b/mediastreamer2
@@ -1 +1 @@
-Subproject commit 756a51419d833105a6378db71679073f6e9492b0
+Subproject commit 73f3e2580927705f26a8eb2e98d8e15606ec6148