gradle: set the aidl with =

The old way is marked as deprecated.

> Properties should be assigned using the 'propName = value' syntax. Setting a
> property via the Gradle-generated 'propName value' or 'propName(value)'
> syntax in Groovy DSL has been deprecated.

application/donations/build.gradle

@@ -70,7 +70,7 @@ android {
     }
     namespace = 'org.videolan.vlc.donations'
     buildFeatures {
-        aidl true
+        aidl = true
         buildConfig = true
     }
 }

application/vlc-android/build.gradle

@@ -121,7 +121,7 @@ android {
     namespace = 'org.videolan.vlc'
     buildFeatures {
         renderScript true
-        aidl true
+        aidl = true
         buildConfig = true
     }
 }

medialibrary/build.gradle

@@ -77,7 +77,7 @@ android {
     }
     buildFeatures {
         renderScript true
-        aidl true
+        aidl = true
     }
 
     // Make per-variant version code