Fix Qt-RangeLoopDetach in qgeofiletilecache.cpp

- introduce an intermediate local const variables.

Axivion-Id: qt_Add-ons_qtlocation_dev_linux:SV236
Axivion-Id: qt_Add-ons_qtlocation_dev_linux:SV237
Axivion-Id: qt_Add-ons_qtlocation_dev_linux:SV238
Axivion-Id: qt_Add-ons_qtlocation_dev_linux:SV239
Task-number: QTBUG-144760
Pick-to: 6.12 6.11 6.8
Change-Id: I939868b09e6ffb6ab833ae3fea8cf0b7b9cab747
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>