Add sendHint method to the PowerHintSession API for load changes

Add a new sendHint(SessionHint hint) method to the PowerHintSession to
allow clients to inform the session about upcoming changes in load ahead
of time.

Bug: b/243973548
Test: atest VtsHalPowerTargetTest
Change-Id: I0a8af42d3b0ccd3bbb72287a9b91ffb13fccaf9c
diff --git a/compatibility_matrices/compatibility_matrix.current.xml b/compatibility_matrices/compatibility_matrix.current.xml
index 71243bf..25d1ae4 100644
--- a/compatibility_matrices/compatibility_matrix.current.xml
+++ b/compatibility_matrices/compatibility_matrix.current.xml
@@ -432,7 +432,7 @@
     </hal>
     <hal format="aidl" optional="false">
         <name>android.hardware.power</name>
-        <version>2-3</version>
+        <version>2-4</version>
         <interface>
             <name>IPower</name>
             <instance>default</instance>