Replace the `createImplicitFiles` method return type with `void`

All instances of the `createImplicitFiles` always return `true` and this
return value is used nowhere.

llvm-svn: 234205
diff --git a/lld/lib/ReaderWriter/MachO/MachOLinkingContext.cpp b/lld/lib/ReaderWriter/MachO/MachOLinkingContext.cpp
index ef28c48..9b5837c 100644
--- a/lld/lib/ReaderWriter/MachO/MachOLinkingContext.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachOLinkingContext.cpp
@@ -685,7 +685,7 @@
     return 0x1000; // 1.0
 }
 
-bool MachOLinkingContext::createImplicitFiles(
+void MachOLinkingContext::createImplicitFiles(
                             std::vector<std::unique_ptr<File> > &result) {
   // Add indirect dylibs by asking each linked dylib to add its indirects.
   // Iterate until no more dylibs get loaded.
@@ -699,7 +699,7 @@
   }
 
   // Let writer add output type specific extras.
-  return writer().createImplicitFiles(result);
+  writer().createImplicitFiles(result);
 }