camera: fix `-Wunused-parameter` compiler warnings

Test: add `USE_CAMERA_V4L2_HAL := true` to
      hardware/libhardware/modules/camera/3_4/Android.mk and build
      mmm hardware/libhardware/modules/camera/3_4
Change-Id: I1bfd688902c78fe69bfbee3bacc73c25a5ef6c5c
Signed-off-by: Sergii Piatakov <sergii.piatakov@globallogic.com>
diff --git a/modules/camera/3_4/metadata/property.h b/modules/camera/3_4/metadata/property.h
index 6884c7d..6a542b2 100644
--- a/modules/camera/3_4/metadata/property.h
+++ b/modules/camera/3_4/metadata/property.h
@@ -41,22 +41,22 @@
   };
 
   virtual int PopulateDynamicFields(
-      android::CameraMetadata* metadata) const override {
+      android::CameraMetadata* /*metadata*/) const override {
     return 0;
   };
 
   virtual int PopulateTemplateRequest(
-      int template_type, android::CameraMetadata* metadata) const override {
+      int /*template_type*/, android::CameraMetadata* /*metadata*/) const override {
     return 0;
   };
 
   virtual bool SupportsRequestValues(
-      const android::CameraMetadata& metadata) const override {
+      const android::CameraMetadata& /*metadata*/) const override {
     return true;
   };
 
   virtual int SetRequestValues(
-      const android::CameraMetadata& metadata) override {
+      const android::CameraMetadata& /*metadata*/) override {
     return 0;
   };