modules/camera: Fix compiler warnings

Change-Id: I9a58f45cbfc09e4e1a243fa657dd0955648bf101
diff --git a/modules/camera/ExampleCamera.cpp b/modules/camera/ExampleCamera.cpp
index 2b1f185..d060d35 100644
--- a/modules/camera/ExampleCamera.cpp
+++ b/modules/camera/ExampleCamera.cpp
@@ -264,7 +264,8 @@
     return setTemplate(CAMERA3_TEMPLATE_ZERO_SHUTTER_LAG, m.get());
 }
 
-bool ExampleCamera::isValidCaptureSettings(const camera_metadata_t* settings)
+bool ExampleCamera::isValidCaptureSettings(
+        const camera_metadata_t* /*settings*/)
 {
     // TODO: reject settings that cannot be captured
     return true;