Make atrace HAL optional

Bug: 111098596
Test: build
Change-Id: I2a18f004926e4488b87dd1d830490717908de963
diff --git a/compatibility_matrices/compatibility_matrix.current.xml b/compatibility_matrices/compatibility_matrix.current.xml
index d9f5ebb..32e1695 100644
--- a/compatibility_matrices/compatibility_matrix.current.xml
+++ b/compatibility_matrices/compatibility_matrix.current.xml
@@ -1,5 +1,5 @@
 <compatibility-matrix version="1.0" type="framework" level="4">
-    <hal format="hidl" optional="false">
+    <hal format="hidl" optional="true">
         <name>android.hardware.atrace</name>
         <version>1.0</version>
         <interface>