tidy: Remove redundant control flow statements.

Clang-tidy pointed out where functions that don't return a value end
with a 'return' statement.  Changes made by the clang-tidy program.

These problems were pointed out by clang-tidy's "redundant control
flow" check.

https://clang.llvm.org/extra/clang-tidy/checks/readability-redundant-control-flow.html

mythtv/libs/libmythui/opengl/mythrenderopengl.cpp

@@ -1402,7 +1402,6 @@ void MythRenderOpenGL::GetCachedVBO(GLuint Type, const QRect &Area)
         vbo->write(0, vertices, kTextureOffset);
     }
     ExpireVBOS(MAX_VERTEX_CACHE);
-    return;
 }
 
 void MythRenderOpenGL::ExpireVBOS(int Max)