android: Remove unnecessary @TargetApi

The minSdkVersion is 21, remove unnecessary @TargetApi annotations.

src/frontends/android/app/src/main/java/org/strongswan/android/logic/CharonVpnService.java

@@ -1236,7 +1236,6 @@ public class CharonVpnService extends VpnService implements Runnable, VpnStateSe
 			}
 		}
 
-		@TargetApi(Build.VERSION_CODES.LOLLIPOP)
 		public void applyData(VpnService.Builder builder)
 		{
 			for (IPRange address : mAddresses)

src/frontends/android/app/src/main/java/org/strongswan/android/ui/TrustedCertificateImportActivity.java

@@ -16,13 +16,11 @@
 
 package org.strongswan.android.ui;
 
-import android.annotation.TargetApi;
 import android.app.Dialog;
 import android.content.ActivityNotFoundException;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.net.Uri;
-import android.os.Build;
 import android.os.Bundle;
 import android.widget.Toast;
 
@@ -61,7 +59,6 @@ public class TrustedCertificateImportActivity extends AppCompatActivity
 		}
 	);
 
-	@TargetApi(Build.VERSION_CODES.KITKAT)
 	@Override
 	public void onCreate(Bundle savedInstanceState)
 	{