Similar to the openocd fix in commit 5966e2dc54 (package/openocd: fix
fallout after no-C++ fixups) the jimctl that is bundled with
usb_modeswitch also wants to find a binary. This broke with commit 4cd1ab158 (core: alternate solution to disable C++). Revert to 'false'
instead of 'no' here as well.