populate_sdk_qt5.bbclass: Fix symlink location for QtCreator use

The QtCreator is quite broken regarding finding the mkspecs files; so
to workaround it we must to add a symlink to it. The workaround was in
place but in the wrong sysroot, it must to be in the /native/ one.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Acked-by: Jonathan Liu <net147@gmail.com>