usbcamera: Fix compiler warnings

Change-Id: Ifc9fec5e90f5295d2b4a5b4c8648510565b9ba17
diff --git a/modules/usbcamera/UsbCamera.cpp b/modules/usbcamera/UsbCamera.cpp
index d0aaded..9d53fc6 100644
--- a/modules/usbcamera/UsbCamera.cpp
+++ b/modules/usbcamera/UsbCamera.cpp
@@ -313,7 +313,7 @@
     return setTemplate(CAMERA3_TEMPLATE_MANUAL, m.get());
 }
 
-bool UsbCamera::isValidCaptureSettings(const camera_metadata_t* settings) {
+bool UsbCamera::isValidCaptureSettings(const camera_metadata_t* /*settings*/) {
     // TODO: reject settings that cannot be captured
     return true;
 }