baremetal: Fix typo in option to enable C++ language for IAR
baremetal: Fix typo in option to enable C++ language for IAR

We need to use the '--c++' option instead of '--ec++'
to dump the macroses and headers for the C++ language.

Change-Id: I545e661babc1ffa84ef189d28b2dd59be3cef29e
Reviewed-by: Qbs CI Bot <94eb2064b2abdc395eb337a66643921d92d5d1fb@weickelt.de>
Reviewed-by: Christian Kandeler <3aa99dcdd3f0cac61fb81c2a11771c0cc2497607@qt.io>

qtproject/qt-labs-qbs,qt-labs/qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qtproject/qt-labs-qbs,qtproject/qt-labs-qbs,qt-labs/qbs,qt-labs/qbs,qt-labs/qbs