Don't access static functions/fields via instance

Courtesy of readability-static-accessed-through-instance

Change-Id: I71f54244f1e091315dac2943d9e1bfad6efa56a9
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/qbsprojectmanager/qbsprofilemanager.cpp

@@ -150,7 +150,7 @@ QString QbsProfileManager::ensureProfileForKit(const ProjectExplorer::Kit *k)
 {
     if (!k)
         return QString();
-    m_instance->updateProfileIfNecessary(k);
+    updateProfileIfNecessary(k);
     return profileNameForKit(k);
 }