Comment out unused parameter in Tuner Frontend implementation

Test: make
Bug: 163870103
Change-Id: Ie02454fca63558d519c34c2566a20d2c1a6958d1
diff --git a/tv/tuner/1.1/default/Frontend.cpp b/tv/tuner/1.1/default/Frontend.cpp
index fde26c1..1e9435b 100644
--- a/tv/tuner/1.1/default/Frontend.cpp
+++ b/tv/tuner/1.1/default/Frontend.cpp
@@ -72,7 +72,7 @@
 }
 
 Return<Result> Frontend::tune_1_1(const FrontendSettings& settings,
-                                  const V1_1::FrontendSettingsExt& settingsExt) {
+                                  const V1_1::FrontendSettingsExt& /*settingsExt*/) {
     ALOGV("%s", __FUNCTION__);
     return tune(settings);
 }