hwc/qdutils/qservice: Add dynamic idle timeout support

Add support for dynamically setting idle timeout values.
Move default idle timeout setting to IdleInvalidator.
Fix static var naming, handle errors from IdleInvalidator in hwc.
Property debug.hwc.idletime is removed with this change.

Example:
1) Set idle timeout to 100ms
adb shell service call display.qservice 16 i32 100
16 is the code for SET_IDLE_TIMEOUT, 100 is time in ms

2) Disable idle timeout
adb shell service call display.qservice 16 i32 0

Change-Id: I60e15a3ac869b4e9f4015b3be50a35c90d00d404
diff --git a/libqservice/IQService.h b/libqservice/IQService.h
index 30c064e..3be20f1 100644
--- a/libqservice/IQService.h
+++ b/libqservice/IQService.h
@@ -53,6 +53,7 @@
         SET_WFD_STATUS,          // Set if wfd connection is on/off
         SET_VIEW_FRAME,          // Set view frame of display
         DYNAMIC_DEBUG,           // Enable more logging on the fly
+        SET_IDLE_TIMEOUT,        // Set idle timeout for GPU fallback
         COMMAND_LIST_END = 400,
     };