OGL/VertexManager: Do not check if g_nativeVertexFmt is zero

The variable is already dereferenced both before and after this
check which means that if this variable would ever be zero it would
have crashed dolphin already.

Source/Core/VideoBackends/OGL/VertexManager.cpp

@@ -158,8 +158,7 @@ void VertexManager::vFlush(bool useDstAlpha)
 	ProgramShaderCache::UploadConstants();
 
 	// setup the pointers
-	if (g_nativeVertexFmt)
-		g_nativeVertexFmt->SetupVertexPointers();
+	g_nativeVertexFmt->SetupVertexPointers();
 	GL_REPORT_ERRORD();
 
 	Draw(stride);