audioflinger: effect: fix deadlock after dumpsys

Bug: 268441977
Test: add a device effect, call dumpsys twice, proxy is marked as "might
be deadlocked"

This CL fixes lock/unlock on the wrong lock

Change-Id: I6923e891a0d87a1be87edbaf44baa554ee729adb
Signed-off-by: François Gaffie <francois.gaffie@renault.com>
diff --git a/services/audioflinger/Effects.cpp b/services/audioflinger/Effects.cpp
index 25c8ac8..6716d73 100644
--- a/services/audioflinger/Effects.cpp
+++ b/services/audioflinger/Effects.cpp
@@ -3485,7 +3485,7 @@
     }
 
     if (locked) {
-        mLock.unlock();
+        mProxyLock.unlock();
     }
 }