Code clean for libcameraservice

Cleaning compile warnings "variable 'XX' set but not used":
1. Remove the variables which are obviously not used;
2. Add "[[maybe_unused]]" to variable declaration of the ones
   which are potentially used.

For the unused function parameters which were cast by "(void)":
We have changed them to the C++17 attribute "[[maybe_unused]]".
This seems not that necessary but it avoids redundant code lines.

Test: mmm frameworks/av/services/camera/libcameraservice,
      presubmit check.

Change-Id: Ia68b78c01f8254d76be81b1ce98d2a5c3d7eea46
Signed-off-by: Jing Mike <jingyangliu@eswincomputing.com>
diff --git a/services/camera/libcameraservice/api2/CameraOfflineSessionClient.cpp b/services/camera/libcameraservice/api2/CameraOfflineSessionClient.cpp
index 2cb3397..acc805a 100644
--- a/services/camera/libcameraservice/api2/CameraOfflineSessionClient.cpp
+++ b/services/camera/libcameraservice/api2/CameraOfflineSessionClient.cpp
@@ -309,26 +309,20 @@
     finishCameraStreamingOps();
 }
 
-void CameraOfflineSessionClient::notifyAutoFocus(uint8_t newState, int triggerId) {
-    (void)newState;
-    (void)triggerId;
-
+void CameraOfflineSessionClient::notifyAutoFocus([[maybe_unused]] uint8_t newState,
+                [[maybe_unused]] int triggerId) {
     ALOGV("%s: Autofocus state now %d, last trigger %d",
           __FUNCTION__, newState, triggerId);
 }
 
-void CameraOfflineSessionClient::notifyAutoExposure(uint8_t newState, int triggerId) {
-    (void)newState;
-    (void)triggerId;
-
+void CameraOfflineSessionClient::notifyAutoExposure([[maybe_unused]] uint8_t newState,
+                [[maybe_unused]] int triggerId) {
     ALOGV("%s: Autoexposure state now %d, last trigger %d",
             __FUNCTION__, newState, triggerId);
 }
 
-void CameraOfflineSessionClient::notifyAutoWhitebalance(uint8_t newState, int triggerId) {
-    (void)newState;
-    (void)triggerId;
-
+void CameraOfflineSessionClient::notifyAutoWhitebalance([[maybe_unused]] uint8_t newState,
+                [[maybe_unused]] int triggerId) {
     ALOGV("%s: Auto-whitebalance state now %d, last trigger %d", __FUNCTION__, newState,
             triggerId);
 }